Essays On The Microscope - free ebook by George Adams

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Essays On The Microscope

George Adams

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ESSAYS ON THE MICROSCOPE.

ESSAYS ON THE MICROSCOPE.

T.S. Duché pinxit Truth discovering to Time, Science instructing her Children in the Improvements on the Microscope. London, Published July 1. st 1787, by Geo. e Adams, N. o 60 Fleet Street. ESSAYS ON THE MICROSCOPE ; CONTAINING A PRACTICAL DESCRIPTION OF THE MOST IMPROVED MICROSCOPES ; A GENERAL HISTORY OF INSECTS, THEIR TRANSFORMATIONS, PECULIAR HABITS, AND ŒCONOMY: AN ACCOUNT OF THE VARIOUS SPECIES, AND SINGULAR PROPERTIES, OF THE HYDRÆ AND VORTICELLÆ: A DESCRIPTION OF THREE HUNDRED AND EIGHT

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PREFACE.

PREFACE.

I n the preface to my Essays on Electricity and Magnetism , I informed the public that it was my intention to publish, from time to time, essays describing the construction and explaining the use of mathematical and philosophical instruments, in their present state of improvement. This work will, I hope, be considered as a performance of my promise, as far as relates to the subject here treated of. [1] [1] Towards the completion of this design, our author afterwards published, 1. Astronomical an

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A LIST OF THE AUTHORS WHICH HAVE BEEN CONSULTED IN THE COMPILATION OF THE FORMER AND PRESENT EDITION OF THESE ESSAYS.

A LIST OF THE AUTHORS WHICH HAVE BEEN CONSULTED IN THE COMPILATION OF THE FORMER AND PRESENT EDITION OF THESE ESSAYS.

London , Dec. 12, 1797 . The Public are hereby respectfully informed, that the Stock and Copyright of the following Works by the same Author , lately deceased, have been purchased by W. and S. Jones , Opticians, &amp;c. and that they are now to be had at their Shop in Holborn. I. GEOMETRICAL AND GRAPHICAL ESSAYS. This Work contains, 1. A select Set of Geometrical Problems, many of which are new, and not contained in any other Work. 2. The Description and Use of those Mathematical Instruments

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ADVERTISEMENT.

ADVERTISEMENT.

T he editor esteems it his indispensable duty, to point out the several improvements which have been made in this work, in order to render it still more acceptable to the public. The whole has been carefully revised—many typographical errors corrected—numerous additions and emendations from the author’s own copy incorporated, and some superfluities rejected. Wherever any ambiguity occurred, the editor has endeavoured to elucidate the passage, observing due caution not to misconceive the idea whi

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ERRATA.

ERRATA.

Page 16, line 22, for lead read led Page 20, line 6, for Fig. T read Fig. 1 Page 49, last line, for usefully read successfully Page 62, last but one, for stop read stage Page 80, line 22, after microscope add by Page 88, three lines from bottom, for improvent read improvement Page 95, line 2, for R read K Page 111, two lines from bottom, for VK read VX Page 115, line 12, for g read q Page 125, note, for Fig. 13 read Fig. 13* Page 145, line 17, for cast of read cast-off Page 153, line 21, for unk

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LIST OF THE PLATES, WITH REFERENCES TO THE PAGES WHERE THE SEVERAL FIGURES ARE DESCRIBED.

LIST OF THE PLATES, WITH REFERENCES TO THE PAGES WHERE THE SEVERAL FIGURES ARE DESCRIBED.

N. B. The reader will find no references to the several letters which appear in the bodies of these figures, for reasons assigned by the author as above; in order not to deface the plate, they were suffered to remain. ESSAYS ON THE MICROSCOPE. I t is generally supposed that microscopes [3] were invented about the year 1580, a period fruitful in discoveries; a time when the mind began to emancipate itself from those errors and prejudices by which it had been too long enslaved, to assert its right

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TO MAKE SMALL GLASS MICROSCOPIC GLOBULES.

TO MAKE SMALL GLASS MICROSCOPIC GLOBULES.

Take two rods of glass, one in each hand, place their extremities close to each other, and in the purest part of the flame; when you perceive the ends to be fused, separate them from each other; the heated glass following each rod, will be finer, in proportion to the length it is drawn to, and the smallness of the rod; in this manner you may procure threads of glass of any degree of fineness. Direct the flame to the middle of the thread, and it will be instantly divided into two parts. When one

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OF THE SINGLE MICROSCOPE.

OF THE SINGLE MICROSCOPE.

The single microscope renders minute objects visible, by means of a small glass globule, or convex lens, of a short focus. Let E Y, Fig. 11. Plate I. represent the eye; and O B a small object, situated very near to it; consequently, the angle of its apparent magnitude very large. Let the convex lens R S be interposed between the eye and the object, so that the distance between it and the object may be equal to the focal length; and the rays which diverge from the object, and pass through the len

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OF THE DOUBLE OR COMPOUND MICROSCOPE.

OF THE DOUBLE OR COMPOUND MICROSCOPE.

In the compound microscope, the image is viewed instead of the object, which image is magnified by a single lens, as the object is in a single microscope. It consists of an object lens N L, Fig. 5. Plate I. and an eye glass F G. The object B O is placed a little further from the lens than its principal focal distance, so that the pencils of rays proceeding from the different points of the object through the lens, may converge to their respective foci, and form an inverted image of the object at

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OF THE SOLAR MICROSCOPE.

OF THE SOLAR MICROSCOPE.

In this instrument, the image of the object is refracted upon a screen in a darkened room. It may be considered under two distinct heads: 1st, the mirror and lens, which are intended to reflect and transmit the light of the sun upon the object; and 2dly, that part which constitutes the microscope, or which produces the magnified image of the object, Fig. 10. Plate I. Let N O represent the side of a darkened chamber, G H a small convex lens, fixed opposite to a perforation in the side N O, A B a

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OF THE MAGNIFYING POWERS OF THE MICROSCOPE.

OF THE MAGNIFYING POWERS OF THE MICROSCOPE.

We have already treated of the apparent magnitude of objects, and shewn that they are measured by the angles under which they are seen, and that this angle is greater or smaller according as the object is nearer to, or further from, the eye; and, consequently, the less the distance at which it can be viewed, the larger it will appear: but from the limits of natural vision, the naked eye cannot distinguish an object that is very near to it; yet, when assisted by a convex lens, distinct vision is

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OF THE NEEDLE MICROMETER.

OF THE NEEDLE MICROMETER.

Fig. 8. Plate II. A , represents this micrometer. The first of this kind was made by my father, and was described by him in his Micrographia Illustrata. It consists of a screw, which has fifty threads to an inch; this screw carries an index, which points to the divisions on a circular plate, which is fixed at right angles to the axis of the screw. The revolutions of the screw are counted on a scale, which is an inch divided into fifty parts; the index to these divisions is a flower de luce marke

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ACCOUNT OF GLASS, PEARL, &c. MICROMETERS, BY THE EDITOR.

ACCOUNT OF GLASS, PEARL, &c. MICROMETERS, BY THE EDITOR.

Having seen some glass, &amp;c. micrometers with exquisite fine divisions, for the purposes of applying to microscopes and telescopes; and in accuracy, being equivalent to the micrometer just described by our author, I judge, some account of their application and uses here will be very acceptable to the curious and inquisitive reader. A particular description of these as made by the ingenious Mr. Coventry, has been already given in the Encyclopædia Britannica, Vol. XI. p. 708. The singular d

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DESCRIPTION OF ADAMS’S IMPROVED AND UNIVERSAL LUCERNAL MICROSCOPE. Fig. 1. Plate III.

DESCRIPTION OF ADAMS’S IMPROVED AND UNIVERSAL LUCERNAL MICROSCOPE. Fig. 1. Plate III.

This microscope was originally thought of, and in part executed by my father; I have, however, so improved and altered it, both in construction and form, as to render it altogether a different instrument. The approbation it has received from the most experienced microscopic observers, as well as the great demand I have had for them, has fully repaid my pains and expenses, in bringing it to its present state of perfection. As the far greater part of the objects which surround us are opake, and ve

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A DESCRIPTION OF THE SEVERAL IMPROVEMENTS MADE UPON MR. ADAMS’S LUCERNAL MICROSCOPE. BY THE EDITOR.

A DESCRIPTION OF THE SEVERAL IMPROVEMENTS MADE UPON MR. ADAMS’S LUCERNAL MICROSCOPE. BY THE EDITOR.

The lucernal microscope being unquestionably the only instrument for exhibiting all sorts of opake objects under a brilliant and magnified appearance, was, as formerly constructed by the late Mr. G. Adams, attended with some inconveniences and imperfections. Upon a proper inquiry into various improvements, and from some observations made by myself, I can recommend, as a complete instrument, one with the following emendations, being, in my opinion, the best of any hitherto made known. The lucerna

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DESCRIPTION OF CUFF’S DOUBLE-CONSTRUCTED MICROSCOPE, REPRESENTED AT Fig. 1. Plate VII. A.[32]

DESCRIPTION OF CUFF’S DOUBLE-CONSTRUCTED MICROSCOPE, REPRESENTED AT Fig. 1. Plate VII. A.[32]

[32] The compound or double microscope is in more general use than any other sort. Besides its being less expensive than the lucernal or complete solar, it is found commodious and portable in the observer’s apartment, when only a confined degree of microscopical pursuit is intended, and that chiefly for a few hours amusement; it may be used both by day and night. In the most improved of this kind the objects appear magnified in a field of view from about 12 to 15 inches in diameter. It is better

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THE DESCRIPTION AND USE OF JONES’S IMPROVED COMPOUND OR DOUBLE MICROSCOPES, REPRESENTED IN Fig. 1 AND 2. Plate IV. BY THE EDITOR.

THE DESCRIPTION AND USE OF JONES’S IMPROVED COMPOUND OR DOUBLE MICROSCOPES, REPRESENTED IN Fig. 1 AND 2. Plate IV. BY THE EDITOR.

The chief imperfections of Cuff’s microscope, as well as of others formerly made, are, their construction rendering them only compound microscopes, the body of the instrument having but a fixed position over the object, and the smallness of the field of view by the old construction of the glasses in the body. To obviate these defects, as well as for the application of material improvements, the late Messrs. Martin and Adams, and the present Messrs. W. and S. Jones, have constructed this kind of

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OF THE MOST IMPROVED COMPOUND MICROSCOPE, BEING UNIVERSAL IN ITS USES, AND FORMING THE SINGLE, COMPOUND, OPAKE, AND AQUATIC MICROSCOPES.

OF THE MOST IMPROVED COMPOUND MICROSCOPE, BEING UNIVERSAL IN ITS USES, AND FORMING THE SINGLE, COMPOUND, OPAKE, AND AQUATIC MICROSCOPES.

A person much accustomed to observations by the microscope, will readily discern the several advantages of this instrument over the preceding one. Besides its containing an additional quantity of useful apparatus, it is more commodious and complete for the management while observing, as it may instantly be placed in a vertical, oblique, or horizontal situation, turned laterally at the ease of the observer, and the objects viewed by the primary direct light, or reflected as usual, at pleasure. Th

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A DESCRIPTION OF CULPEPER’S, OR THE COMMON THREE-PILLARED MICROSCOPE. Plate IV. Fig. 3.

A DESCRIPTION OF CULPEPER’S, OR THE COMMON THREE-PILLARED MICROSCOPE. Plate IV. Fig. 3.

The only recommendations of this original instrument are, its simple construction and lowness of price. It gives a pleasing view of the object. It is precluded by its form from some of the advantages of the two foregoing instruments, because both the stage and the mirror are confined. This microscope consists of a large exterior brass body, A B, supported on three brass scrolls, which are fixed to the stage F; the stage is supported by three larger scrolls that are screwed to the mahogany pedest

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A DESCRIPTION OF MARTIN’S IMPROVED SOLAR MICROSCOPE, WHICH IS CONSTRUCTED TO EXHIBIT TRANSPARENT AND OPAKE OBJECTS. Plate V.

A DESCRIPTION OF MARTIN’S IMPROVED SOLAR MICROSCOPE, WHICH IS CONSTRUCTED TO EXHIBIT TRANSPARENT AND OPAKE OBJECTS. Plate V.

The solar microscope is generally supposed to afford the most entertainment, on account of the wonderful extent of its magnifying power, and the ease with which several persons may view each single object at the same time. The use of it was, however, confined for many years only to transparent objects. About the year 1774, Mr. B. Martin so far improved this instrument, as to render it applicable to opake, as well as to transparent objects, exhibiting the magnified image of either kind on a large

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DESCRIPTION OF THE TRANSPARENT SOLAR MICROSCOPE AND APPARATUS. Plate VI. Fig. 4, to 14.

DESCRIPTION OF THE TRANSPARENT SOLAR MICROSCOPE AND APPARATUS. Plate VI. Fig. 4, to 14.

The foregoing description will, in great part, answer for this microscope; but, the dimensions, apparatus, &amp;c. varying in a small degree from the preceding, a distinct description here, may be acceptable to those, who possess this sort of microscope only. A B C D, Fig. 4, represents the body of the microscope, consisting of two brass tubes. E F is the end of the inner moveable tube; e f , that of the single tooth and pinion microscope. Fig. 5, screws into the end of this inner tube; at t

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THE SCREW BARREL, OR WILSON’S SINGLE POCKET MICROSCOPE. Plate II. B. Fig. 1 and 2.

THE SCREW BARREL, OR WILSON’S SINGLE POCKET MICROSCOPE. Plate II. B. Fig. 1 and 2.

This microscope of Mr. Wilson’s is an invention of many years standing, and was in some measure laid aside, till Dr. Lieberkühn introduced the solar apparatus to which he applied it, there being no other instrument at that time which would answer his purpose so well; it is much esteemed in particular cases. The body of the microscope is represented at A B, Fig. 1, and is made either of silver, brass, or ivory. C C is a long fine-threaded male screw, that turns into the body of the microscope. D,

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DESCRIPTION OF A SMALL MICROSCOPE FOR OPAKE OBJECTS. Plate II. B. Fig. 3 and 4.

DESCRIPTION OF A SMALL MICROSCOPE FOR OPAKE OBJECTS. Plate II. B. Fig. 3 and 4.

A, Fig. 3, is a fixed arm, through which passes a screw, B, the other end is fastened to the moveable arm, C. D, a nut fitted to the said screw, which, when turned, will either separate or bring together the two arms, A C. E, a steel spring, that separates the two sides when the nut is unscrewed. F, a piece of brass turning round in a spring socket, moving on a rivet, in which moves a steel wire pointed at the end G, and the other end a pair of pliers, H: these are either to thrust into, or take

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OF ELLIS’S SINGLE OR AQUATIC MICROSCOPE. Plate VII. B.

OF ELLIS’S SINGLE OR AQUATIC MICROSCOPE. Plate VII. B.

This instrument takes its name from Mr. John Ellis, author of “An Essay towards a Natural History of Corallines,” and of the “Natural History of many curious and uncommon Zoophytes.” By this instrument he was enabled to explain many singularities in the œconomy and construction of these wonderful productions of nature. To the practical botanist this instrument is recommended by the respectable authority of Mr. Curtis, author of the Flora Londinensis, a work which does credit to the author and th

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DESCRIPTION OF LYONET’S ANATOMICAL MICROSCOPE. Plate VI. Fig. 3.

DESCRIPTION OF LYONET’S ANATOMICAL MICROSCOPE. Plate VI. Fig. 3.

Fig. 3 represents the instrument with which M. Lyonet made his microscopical and wonderful dissection of the chenille de saule or caterpillar of the goat moth, [36] of which a specimen is given in Plate XII. Fig. 1, &amp;c. of this work. This portable instrument needs no further recommendation. By it, other observers may be enabled to dissect insects in general with the same accuracy as M. Lyonet, and thus advance the knowledge of comparative anatomy, by which alone the characteristic, natur

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DR. WITHERING’S BOTANICAL MICROSCOPE. Plate VI. Fig. 1.

DR. WITHERING’S BOTANICAL MICROSCOPE. Plate VI. Fig. 1.

This small instrument consists of three brass parallel plates, A, B, C; two wires, D and E, are rivetted into the upper and lower plate; the middle plate or stage is moveable on the aforesaid wires, by two little sockets which are fixed to it. The two upper plates each contain a magnifying lens, but of different powers; one of these confines and keeps in their places the fine point F, the forceps G, and the small knife H. To use this instrument, unscrew the upper lens, and take out the point, th

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THE POCKET BOTANICAL AND UNIVERSAL MICROSCOPE.

THE POCKET BOTANICAL AND UNIVERSAL MICROSCOPE.

This pocket instrument is represented at Plate VI. Fig. 2. It is by most naturalists deemed preferable to Dr. Withering’s, being equally simple, more extensive in its application, and the stage unincumbered; though that of M. Lyonet seems better adapted than either to the purposes of dissection only. A B, a small arm, carrying three magnifiers, two fixed to the upper part, as at B, the other to the lower part of the arm, at C; these may be used separately or combined together, by which you have

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BOTANICAL MAGNIFIERS.

BOTANICAL MAGNIFIERS.

Since botany has been cultivated with so much ardor, it has been found necessary to contrive some very portable instrument, by which the botanist might investigate the object of his pursuits as it rises before him. Plate VIII. Fig. 7 and 8, represent two of the most convenient sort. In the tortoiseshell case, Fig. 7, three lenses are contained, d , e , f , of different foci, which are all made to turn into the case, and may be used combined or separately. The three lenses in themselves afford th

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DESCRIPTION OF A PORTABLE MICROSCOPE AND TELESCOPE. Plate VIII. Fig. 1, to 6.

DESCRIPTION OF A PORTABLE MICROSCOPE AND TELESCOPE. Plate VIII. Fig. 1, to 6.

The telescope is one of those which are composed of several sliding drawers or tubes, for the convenience of being put into the pocket; the sliding tubes are made of thin brass, the outside tube of mahogany. The sliding tubes are contrived to stop, when drawn out to a proper length, so that by applying one hand to the outside tube, and the other hand to the end of the smallest tube, the telescope may at one pull be drawn out to its full length; then any of the tubes (that next the eye is most ge

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DESCRIPTION OF AN INSTRUMENT FOR CUTTING THIN TRANSVERSE SECTIONS OF WOOD, Plate IX. Fig. 1.

DESCRIPTION OF AN INSTRUMENT FOR CUTTING THIN TRANSVERSE SECTIONS OF WOOD, Plate IX. Fig. 1.

It consists of a wooden base, which supports four brass pillars; on the top of the pillars is placed a flat piece of brass, near the middle of which there is a triangular hole. A sharp knife which moves in a diagonal direction, is fixed on the upper side of the afore-mentioned plate, and in such a manner, that the edge always coincides with the surface thereof. The knife is moved backwards and forwards by means of the handle, a . The piece of wood is placed in the triangular trough, which is und

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OF THE NECESSARY PREPARATION OF THE MICROSCOPE FOR OBSERVATION.

OF THE NECESSARY PREPARATION OF THE MICROSCOPE FOR OBSERVATION.

We have in the last chapter explained those particulars that constitute the difference of one microscope from another, and shewn the manner of using each instrument, and how the several parts are to be applied to it. We shall now proceed to give some general directions applicable to every microscope. The observer is therefore supposed to have made himself master of his instrument, and to know how to adapt the different parts of the apparatus to their proper places. The first circumstance necessa

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OF THE MANAGEMENT OF THE LIGHT.

OF THE MANAGEMENT OF THE LIGHT.

The pleasure arising from a just view of a microscopic object, the distinctness of vision, &amp;c. depend on a due management of the light, and adapting the quantity of it to the nature of the object, and the focus of the magnifier; therefore, an object should always be viewed in various degrees of light. It is difficult to distinguish in some objects between a prominency and a depression, between a shadow and a black stain; and in colour, between a reflection and a whiteness; a truth which

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OF THE PREPARATION OF OBJECTS FOR THE MICROSCOPE.

OF THE PREPARATION OF OBJECTS FOR THE MICROSCOPE.

In the preparation of objects, no man was more successful or more indefatigable than Swammerdam. In minutely anatomizing, in patiently investigating, and in curiously exhibiting the minute wonders of the creation, he stands unrivalled, far exceeding all those that preceded, as well as those which have succeeded him. Deeply impressed and warmly animated by the amazing scenes that he continually discovered, his zeal in pursuit of truth was not to be abated by disappointment, or alarmed by difficul

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A GENERAL DESCRIPTION OF INSECTS.

A GENERAL DESCRIPTION OF INSECTS.

The subjects of that part of the creation we are now going to survey, merit our attention as exceeding the rest of animated nature in their numbers, the singularity of their appearance, and the variety of their forms. Earth, air, and water are filled with hosts of them. Being for the major part very small, and myriads so diminutive, as even to be imperceptible to the unassisted eye, our knowledge of them, and their component parts would be extremely circumscribed and imperfect, were it not for t

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DISTINGUISHING CRITERIA OF INSECTS.

DISTINGUISHING CRITERIA OF INSECTS.

It has already been observed, that the bodies of insects are covered with a hard skin, answering the purpose of an internal skeleton, and forming one of the characters by which they are distinguished from other animals. This external covering is very strong in those insects which, from their manner of life, are particularly liable to great friction, or violent compression; but is more tender and delicate in such as are not so exposed. The skin of insects, like that of larger animals, is porous;

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OF THE TRANSFORMATION OF INSECTS.

OF THE TRANSFORMATION OF INSECTS.

Insects are farther distinguished from other animals by the wonderful changes that all those of the winged species without exception, and some which are destitute of wings, must pass through, before they arrive at the perfection of their nature. Most animals retain, during their whole life, the same form which they receive at their birth; but insects go through wonderful exterior and interior changes, insomuch that the same individual, at its birth and middle state, differs essentially from that

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OF THE SILK-WORM.

OF THE SILK-WORM.

The industry of those that spin cones or cases, in which they inclose themselves, in order to prepare for their transformation in security, is more generally known, as it is from one species of these that we derive so many benefits, namely from the silk-worm, whose works afford an ornament for greatness, and add magnificence to royalty. All caterpillars undergo similar changes with it, and many in the butterfly state greatly exceed it in beauty: but the golden tissue, in which the silk-worm wrap

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OF THE BEETLE.

OF THE BEETLE.

To make the reader more fully acquainted with a subject which affords such abundant matter for the exercise of his microscope, I shall proceed to describe, in as concise a manner as I am able, the changes of a few insects of different classes, beginning with the beetle. The beetle is of the first or coleopterous class, having four wings. The two upper ones are crustaceous, and form a case to the lower ones; when they are shut, there is a longitudinal suture down the back: this formation of the w

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OF THE MUSCA CHAMÆLEON.

OF THE MUSCA CHAMÆLEON.

I shall now proceed to illustrate the nature of the different transformations in insects, by giving an account of the musca chamæleon. In the worm or larva condition it lives in the water, breathes by the tail, and carries its legs within a little snout near its mouth. When the time arrives for its pupa state, it goes through the change without casting off the skin of the larva. Lastly, in the imago, or fly state, it would infallibly perish in the water, that element which had hitherto supplied

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OF THE LIBELLULA OR DRAGON FLY.

OF THE LIBELLULA OR DRAGON FLY.

In the libellula we have an instance of those insects which are termed in the pupa state, semicompleta, that is, such as proceed from the egg in the figure which they preserve till the time arrives for assuming their wings; and who walk, act, and eat as well before that period as afterwards. Of all the flies which adorn or diversify the face of nature, there are few, if any, more beautiful than the libellulæ: they are almost of all colours, green, blue, crimson, scarlet, and white; some unite a

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OF THE RESPIRATION OF INSECTS.

OF THE RESPIRATION OF INSECTS.

As respiration is one of the most important actions in the life of every animal, great pains have been taken by many naturalists to investigate the nature of this action in insects; to prove its existence, and explain in what manner it is carried on. Malpighi, Swammerdam, Reaumur, and Lyonet have discovered in the caterpillar two air-vessels placed the whole length of the insect, these they have called the tracheæ; they have also shewn that an infinite number of ramifications proceed from these,

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OF RESPIRATION IN THE LARVA OF THE MUSCA PENDULA.

OF RESPIRATION IN THE LARVA OF THE MUSCA PENDULA.

Among the insects in which respiration seems to be most clearly proved, are the larvæ of the musca pendula, Lin. These, while in the worm state, live under water in the mud, to which they affix themselves; the respiration of fresh air in this situation is necessary to their existence; for this purpose they are furnished with a tail, which often appears of an excessive length comparatively with the body, as this is seldom more than three quarters of an inch in length, while the tail is frequently

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OF THE GENERATION OF INSECTS.

OF THE GENERATION OF INSECTS.

One of the greatest mysteries in nature is generation, or that power by which the various species of animals, &amp;c. are propagated, enabling one single individual to give birth to thousands, or even millions of individuals like itself; all formed agreeable to proportions which are only known to that ADORABLE WISDOM which has established them. We shall never be able to form any adequate conception of this power, till we are acquainted with the principles of life, and can trace their various

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OF THE APHIDES OR PUCERONS.

OF THE APHIDES OR PUCERONS.

These are a species of insects that have opened new views of the œconomy of animated beings; they belong to the hemiptera class. The rostrum is inflected, the antennæ are longer than the thorax; some have four erect wings, others are entirety without them. Towards the end of the abdomen there are two tubes ejecting that most delicate juice called honey-dew. Various names have been applied to them, the proper one is aphis, that by which they are most generally known, is puceron; they are also fre

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OF THE APIS OR BEE.

OF THE APIS OR BEE.

The bee belongs to the hymenoptera order, the mouth is furnished with two jaws, and a proboscis protected by a double sheath, see Fig. 3. Plate XIII. They have four wings; when these are at rest, the two foremost cover those behind. There is a sting in the tail of the working and female bee. Of the bee kind fifty-five species are enumerated by Linnæus. Our present observations are confined to the common or domestic bee. In the natural history of insects new objects of surprize are continually ri

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OF THE EGGS OF INSECTS.

OF THE EGGS OF INSECTS.

The eggs are contained and arranged in the body of the insect, in vessels which vary in number and figure in different species; the same variety is found in the eggs themselves: some are round, others oval, some cylindrical, and others nearly square; the shells of some are hard and smooth, while others are soft and flexible. It is a general rule, that eggs do not increase in size after they are laid; among insects, we find however an exception to this; the eggs of the tenthredo of Linnæus increa

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OF THE FOOD OF INSECTS.

OF THE FOOD OF INSECTS.

There are few, if any, productions either of the animal or vegetable kingdoms, which do not supply some kind of insect with food. They may, therefore, be considered under two heads, those which live on vegetables, and those which are supported by animal food; each insect knows that which is proper to sustain its life, where to seek it, and how to procure it. I have already observed, that several insects, when arrived at a state of perfection, feed after their transformation upon food totally dif

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OF THE HABITATION OF INSECTS.

OF THE HABITATION OF INSECTS.

Insects may be divided, with respect to their habitations, into two classes, aquatic and terrestrial. Stagnant waters are generally filled with insects, who live therein in different manners. These are, 1. Aquatic insects which remain always on the superficies of the water, or which at least plunge themselves therein but rarely. 2. Others that live only in the water, and cannot subsist out of it. 3. Many, after having lived in the water while in the larva and pupa state, quit it afterwards with

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OF THE TERMITES, GENERALLY CALLED WHITE ANTS.

OF THE TERMITES, GENERALLY CALLED WHITE ANTS.

As no insects exceed the termites in their wonderful œconomy, wise contrivances, and stupendous buildings, it will be proper to give the reader some account of them; which I am enabled to do from the excellent paper written by the late Mr. Smeathman, and published in the Philosophical Transactions for the year 1781, part 1. The termites are represented by Linnæus as the greatest plagues of both Indies, and are indeed justly deemed so every where between the tropics, on account of the vast damage

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OF THE HABITATIONS OF CATERPILLARS.

OF THE HABITATIONS OF CATERPILLARS.

Though the view which has already been given of the various proceedings of insects in forming their habitations, has extended to some length, I cannot with propriety omit noticing the wonderful art and industry which is manifested in these respects by the caterpillar; and more particularly so, as from the larva state the foundation of all our present knowledge of the natural history of insects has been obtained. Some species of caterpillars form a kind of hammock, in which they eat and go throug

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A GENERAL VIEW OF THE INTERIOR PARTS OF THE CATERPILLAR.

A GENERAL VIEW OF THE INTERIOR PARTS OF THE CATERPILLAR.

The MUSCLES have neither the exterior form, nor the colour of those of larger animals. In their natural state they are soft, and have the appearance of a jelly; they are of a greyish blue, and the silver-coloured appearance of the aerial or pulmonary vessels, which creep over and penetrate their substance, exhibits under the microscope a most beautiful spectacle. When the caterpillar has been soaked for some time in spirit of wine, they lose their elasticity and transparency, and become firm, op

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A DESCRIPTION OF SUNDRY MISCELLANEOUS OBJECTS, EXHIBITED IN SEVERAL PLATES OF THIS WORK.

A DESCRIPTION OF SUNDRY MISCELLANEOUS OBJECTS, EXHIBITED IN SEVERAL PLATES OF THIS WORK.

Plate XIII. Fig. 1 and 2. This is a tender and brittle shell-fish of a very peculiar species; its length is about an inch, and its diameter about three quarters of an inch. The shell is not composed of two pieces or valves, as in others, but of five; two of these are larger than the rest, to which are affixed two smaller ones; the fifth piece is long, slender, and crooked, running down length-ways, and covering the joinings of the other pieces. The shell part is of a pale red, variegated with wh

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HYDRA.[111]

HYDRA.[111]

Flos: os terminale, cinctum cirris setaceis. Stirps vaga, gelatinosa, uniflora, basi se affigens. [112] [108] Philosophical Transactions. [109] Micrographia Illustrata. [110] Natural History of the Polype. [111] The hydræ or polypes have generally been denominated Insects: is there not a manifest impropriety in the application of this term to them? If we admit of the systematic arrangement of Linnæus , we find that he has divided the animal kingdom into six classes: 1. Mammalia. 2. Aves. 3. Amph

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OF THE VORTICELLÆ.

OF THE VORTICELLÆ.

We now come to another division of these animals, to which later writers have given the name of vorticellæ; this term I shall therefore adopt, being of opinion that it behoves every man to maintain that order in scientific arrangement which is not inconsistent with truth, except he can produce another arrangement more expressive of the nature of the objects it is designed to discriminate; a process requiring no small degree of attention. The variety that may be observed in these minute animals c

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A METHODICAL DIVISION OF THE ANIMALCULA INFUSORIA.

A METHODICAL DIVISION OF THE ANIMALCULA INFUSORIA.

I. THOSE THAT HAVE NO EXTERNAL ORGANS. 1. Monas : punctiforme. A mere point. 2. Proteus : mutabile. Mutable, or changeable. 3. Volvox : sphæricum. Spherical. 4. Enchelis : cylindraceum. Cylindrical. 5. Vibrio : elongatum. Long. Membranaceous. 6. Cyclidium : ovale. Oval. 7. Paramæcium : oblongum. Oblong. 8. Kolpoda : sinuatum. Crooked, or bent. 9. Gonium : angulatum. With angles. 10. Bursaria . Hollow like a purse. II. THOSE THAT HAVE EXTERNAL ORGANS. Naked, or not inclosed in a shell. 1

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ADDITIONAL ANIMALCULA INFUSORIA, EXHIBITED IN PLATE XXVI.

ADDITIONAL ANIMALCULA INFUSORIA, EXHIBITED IN PLATE XXVI.

378. Fig. A A A . An animalculum found in ditch water in the month of September, represented in three different forms which it assumed. 379. Fig. B B B . A species of testaceous wheel-animal; a , its appearance when protruded; b , when in the shell; c , another appearance of the same. 380. Fig. C , shews one of the same species; and 381. Fig. D , exhibits another of the same kind; they both appear as protruded from the shell. The above are all drawn as they were found adhering to a vegetable sub

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OF THE RIND.

OF THE RIND.

The exterior covering of all trees is a thin, dry, parched substance, which has been compared by many writers to the skin of animals, and called by names analogous thereto; thus it is called the epidermis by Duhamel, the skin by Grew, the rind by Hill. When a tree is full of sap, this membrane may be easily detached from the part it covers; it may be separated from green branches which are not in sap, by boiling them in water; large pieces of it may also be obtained from rotten branches; the rin

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OF THE VESSELS WHICH ARE CONTAINED BETWEEN THE RIND AND THE BARK.

OF THE VESSELS WHICH ARE CONTAINED BETWEEN THE RIND AND THE BARK.

These are called by Du Hamel the cellular coat, enveloppe cellulaire; by Hill, the exterior vessels, and the vasa propria exteriora. It has been already observed, that in trees the juice vessels, or vasa propria, do not form those constituent parts of the wood of which the timber consists, but that it is from the nature of these recipient vessels that it derives its virtues, qualities, and specific properties. [133] A tree may grow, live, and give shade without them; but on those its peculiar ch

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OF THE BARK.

OF THE BARK.

The bark lies next within the rind, and differs but little from it in construction, though it holds a more important office in the scale of vegetation, the growth and qualities of the tree being in a great measure connected with it. It is, therefore, found to differ considerably in substance, quantity, and quality, in various kinds. It is originally the outer membrane, covering the lobes of the seed. Even there, as in the branch of a tree, it appears in the form of a kind of spunge, or like a cr

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OF THE CELLULAR TISSUE.

OF THE CELLULAR TISSUE.

We now proceed to give some account of the substance which fills up the vacant spaces that are left between the longitudinal fibres. It is called by Grew the parenchyma or pulp, by Malpighi, the vesicular tissue or web; both of them consider it as formed of small bladders or reticles, that are in contact with each other, lying in an horizontal position, or at right angles to the longitudinal fibres: they do not suppose them to be all of the same size, or even of the same figure: Grew compares it

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OF THE VASA PROPRIA INTERIORA.

OF THE VASA PROPRIA INTERIORA.

Besides the lymphatic vessels and the cellular substance, we find the juice vessels, or vasa propria, in the bark. In those trees which are famous for medicinal virtues, they are usually very large; they carry the milky juices of the sumach, and in them is lodged the finest and highest-flavoured turpentine in all the kinds of pine. Dr. Hill thinks that a tree of that genus exhibits them best, and the more, as the turpentine which fills them may be perfectly dissolved in spirit of wine. The pinus

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OF THE BLEA.

OF THE BLEA.

This is that part of the tree which is formed into wood, and therefore lies between it and the bark, and may be separated from them by maceration. A longitudinal piece of the blea, when examined by the microscope, exhibits a number of vessels running parallel to each other, the interstitial spaces being filled with a floccose, white, formless substance, of which Dr. Hill suspects even the vessels themselves to be formed. Innumerable small openings or mouths may be discovered in these vessels, su

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OF THE WOOD.

OF THE WOOD.

When the bark and the blea are taken away, we come to the wood, which is a solid substance, on which the strength of the tree depends, and which has been considered by naturalists as being to the tree what bones are to the animal. The wood, in a general view may be considered as formed of strata, which are inclosed one within the other; these strata consist of ligneous fibres or lymphatic vessels, the cellular web or tissue, vasa propria, and what have been called the air vessels. It is more dif

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OF THE CORONA.

OF THE CORONA.

Dr. Hill gives this name to that circle which surrounds the pith, and separates it from the wood; although in his opinion it differs greatly from both, and in its composition has no resemblance to either. It is, according to him, the most important part in the whole vegetable fabric, by which the propagation and increase of the branches, buds, and shoots, are carried on. [137] [137] Hill on the Construction of Timber, p. 55. It has been usual to suppose the pith of vegetables to be the part in w

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OF THE PITH.

OF THE PITH.

The pith is found in the center of every young shoot of a tree; it is large in some, less in others, but present in all. It is placed close within the corona. It seems to be nothing more than a congeries of the cellular tissue; it is generally found near the center of the tree, inclosed as it were within a tube; in general, the cells of the pith are larger than those of the cellular tissue, with which, according to Du Hamel, it communicates. For the rays which extend from the pith to the bark ar

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OF THE SAP VESSELS.

OF THE SAP VESSELS.

The most numerous and the largest apertures are generally to be found in the wood, which are perceived very distinctly in a transverse section, in which the ends of the vessels are seen as cut through by the knife. The scarlet oak of America is recommended as a proper object for exhibiting them. If a short cylinder of a three years branch of this oak, a little macerated, be hollowed away with a chissel, we shall see what a large portion of the wood is occupied by these vessels; they are thick an

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OF THE VASA PROPRIA INTIMA.

OF THE VASA PROPRIA INTIMA.

These are the only vessels which remain to be spoken of. They are large, conspicuous, and important; their natural place is in the blea, though they are sometimes repeated in the wood and the corona. Their coats are thicker than those of any other vessels. [141] It is not difficult, after a successful maceration, to separate some of these vessels from the blea; in this state they appear perfect cylinders, with thick white coats, of a firm, solid, and uniform texture. [141] Hill’s Construction of

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A CONCISE LIST OF OBJECTS FOR THE MICROSCOPE.

A CONCISE LIST OF OBJECTS FOR THE MICROSCOPE.

The short list here presented to the reader must, from the nature of the subject, be very imperfect; for the whole of the animal, vegetable, and mineral kingdoms, with all their numerous subdivisions, furnish objects for the microscope; and there is not one of them, that, when properly examined, will not afford instruction and entertainment to the rational investigator of the works of creation. The Systema Naturæ of Linnæus may therefore be regarded as a catalogue of universals for microscopic o

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A DESCRIPTION AND ARRANGEMENT OF MINUTE AND RARE SHELLS.[154]

A DESCRIPTION AND ARRANGEMENT OF MINUTE AND RARE SHELLS.[154]

[154] Being possessed of Mr. Jacob’s own corrected copy of the work, to which he has annexed the trivial names, I am thereby enabled to affix them to the several shells here enumerated. Plate XIV. Fig. 2. S. bicornis ventricosa. The bellied semilunar worm-shell. The colour white, opake, and glossy. From Sandwich and Reculver, though not common. Fig. 3. S. bicornis umbilico perforato. The semilunar perforated worm-shell. The colour white, opake, and glossy. From Sandwich: very rare. Fig. 4. S. te

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A DESCRIPTIVE LIST OF A VARIETY OF VEGETABLE SEEDS.[155]

A DESCRIPTIVE LIST OF A VARIETY OF VEGETABLE SEEDS.[155]

[155] To the names as given by Dr. Parsons, those adopted by Linnæus are here added. Plate XV. Fig. 1. Ibid. Linn. Gromwell. This seed is in figure exactly like a human heart without the auricles, but has no flat or depressed part on its sides; it is pretty circular round its thickest part, and terminates in a blunt cone. At the thickest extremity there is a circular roughness, which is the umbilicus, and from thence to the cone on the shortest side it is bisulcated longitudinally; so that the s

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THE METHOD OF PROCURING MOTHS AND BUTTERFLIES.

THE METHOD OF PROCURING MOTHS AND BUTTERFLIES.

There are two methods of collecting insects of this kind; first, by breeding; secondly, by catching them in their fly state: of these, the former is by much the preferable mode; as, besides the pleasure which arises from observing the gradual progress of the insects from their egg or caterpillar to their perfect or fly state, they may be killed before they have sustained the smallest injury in the farina or meal of their wings by flying. The difficulty likewise in procuring the most beautiful an

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THE METHOD OF COLLECTING MOTHS, &C. IN THEIR CATERPILLAR STATE.

THE METHOD OF COLLECTING MOTHS, &C. IN THEIR CATERPILLAR STATE.

Independent of the method of collecting caterpillars by an attentive examination of the leaves, and other parts of plants, at those times of the year when they are in full verdure, there is another, viz. by beating the boughs of trees, particularly the taller ones, with long poles, having previously spread a large sheet underneath to receive them as they drop from the trees. By these means many very valuable caterpillars are frequently obtained, which could not otherwise be procured without cons

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THE METHOD OF REARING OR BREEDING THEM.

THE METHOD OF REARING OR BREEDING THEM.

Having procured the caterpillars, our next endeavour must be to rear them. For this purpose; it will be indispensably necessary to afford them an ample supply of the plant on which they are found feeding, and to renew their food as often as the decay of that first procured for them may render it expedient. Insects in this state usually feed voraciously; the caterpillar of the papilio brassica has been known to consume in one day twice its own weight of food. Although many of them live on a varie

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THE METHOD OF COLLECTING THEM IN THEIR CHRYSALIS STATE.

THE METHOD OF COLLECTING THEM IN THEIR CHRYSALIS STATE.

Butterflies and moths may often be found in chrysalis under the projection of garden walls, pales, out-houses, in summer-houses, &amp;c. and frequently affixed to the food on which the caterpillar fed. A great variety of moths in the pupa state may with more certainty be found, during the winter months, by digging under the trees on which they feed, particularly under the oak, willow, lime, and elm trees. When they are procured in this manner, they should be placed as soon as convenient in t

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THE METHOD OF COLLECTING THEM IN THEIR FLY OR PERFECT STATE.

THE METHOD OF COLLECTING THEM IN THEIR FLY OR PERFECT STATE.

The extreme delicacy of the wings of moths and butterflies will not admit of their being caught without injury, but in nets made of the finest materials. It will be necessary, therefore, that the collector should provide himself with a net properly adapted to this purpose: the one here represented has, after long experience, been found to answer extremely well. Fig. A shews the net expanded ready for use; a exhibits the part made of fine Scotch gauze, which should be previously dyed green; b b ,

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THE METHOD OF MANAGING THEM IN THEIR FLY STATE.

THE METHOD OF MANAGING THEM IN THEIR FLY STATE.

Though by the means just described these insects may be caught uninjured, some farther care is requisite in order to make them appear to advantage; this is called setting them, and is performed in the following manner. The insect being stuck through with a pin of a proper size, is to be placed before its wings are become stiff, on a piece of cork, having a smooth surface and covered with white paper. The body of the fly should not be made to touch the cork when the insect is affixed to it, but t

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THE METHODS OF COLLECTING INSECTS OF THE BEETLE KIND.

THE METHODS OF COLLECTING INSECTS OF THE BEETLE KIND.

By these are meant all such, as are included in Linnæus’s first order of insects, under the term COLEOPTERA ; these have generally been called scarabæi or beetles: some few of them have obtained distinct English names, as the chaffer, lady-bird, earwig, &amp;c. and all have been divided by Linnæus into genera and species. The insects of this, as well as the preceding and following order, may be found in their caterpillar or grub state, in which they often prove extremely destructive to the r

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THE METHOD OF COLLECTING INSECTS CALLED HEMIPTERA.

THE METHOD OF COLLECTING INSECTS CALLED HEMIPTERA.

The genera contained in this order of insects are principally these: viz. blatta, the cockroach; mantis, camel cricket; gryllus, locust, grasshopper, cricket; cicada, flea locust; cimex or bug. The first of these, the cockroach, has been imported from warmer climates, where these insects are extremely numerous, and far more troublesome. [164] They are found in the greatest plenty here in bakehouses, particularly in the night, their usual time of feeding; they likewise abound in corn-mills, in sh

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THE METHOD OF COLLECTING INSECTS CALLED NEUROPTERA.

THE METHOD OF COLLECTING INSECTS CALLED NEUROPTERA.

Those of this class, the fourth order of Linnæus, are chiefly aquatic, residing in the waters as caterpillars, and flying about them in their perfect state. The principal genera are, the libellula, dragon-fly; ephemera, may-fly; phryganea, spring-fly; hemerobius, and panorpa. The libellulæ are considered by the generality of people as containing in them something venomous; and from hence, in addition to the epithet, alone sufficiently tremendous, of dragon-fly, have obtained the several names of

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THE METHOD OF COLLECTING INSECTS CALLED HYMENOPTERA.

THE METHOD OF COLLECTING INSECTS CALLED HYMENOPTERA.

The remarks which have just been made on the libellulæ do not apply to insects of this order, the major part of them being armed with stings; some of which are, however, harmless, though others are venomous. The principal genera are, the tenthredo, saw-fly; ichneumon, ichneumon-fly; sphex, ichneumon-wasp; vespa, wasp, hornet; apis, bee; formica, ant; sirex, and chrysis. The tenthredines are found on trees and flowers in their caterpillar state; they feed on the leaves of plants. The ichneumons a

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THE METHOD OF COLLECTING INSECTS CALLED DIPTERA.

THE METHOD OF COLLECTING INSECTS CALLED DIPTERA.

This order contains various kinds of flies and gnats; the former abound in almost every place, but they are found more particularly on all kinds of plants and flowers, especially on the umbelliferous ones, about the tops of trees, little hills, &amp;c. Some of them fly about cattle of various kind, in the skins of which they deposit their eggs, as the oestrus bovis, &amp;c. These insects are easily killed by a few drops of spirit of turpentine: their wings are to be expanded so that thei

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GENERAL INSTRUCTIONS FOR FITTING UP A CABINET.

GENERAL INSTRUCTIONS FOR FITTING UP A CABINET.

To those who delight in subjects of natural history, a good cabinet of insects is esteemed a valuable acquisition: if it be well constructed, and the several objects arranged with judgment, it certainly exhibits one of the most beautiful and admirable assemblages of objects in nature. Such, however, who are disposed to make a collection sufficiently extensive to form a complete one, will find it necessary to devote a great deal of time to the purpose, as well as to be endued with a considerable

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A COPIOUS LIST OF MICROSCOPIC OBJECTS.

A COPIOUS LIST OF MICROSCOPIC OBJECTS.

In the introductory part to our author’s list of objects in Chap. X. he very justly observes, that from the nature of the subject the list must be very imperfect, &amp;c. it is not with the vain idea of rendering that complete which he has left imperfect, and which indeed must ever remain so, that the following general list is introduced; but principally with the view of still farther assisting the tyro, and pointing out a variety of articles, that might not otherwise so readily occur to him

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ADDITIONS.

ADDITIONS.

The following is a new, useful, and ready method of making globules for microscopes, differing from the customary one described in page 8 , and is extracted from Mr. W. Nicholson’s scientifical Journal of Natural Philosophy, Chemistry, and the Arts. No. 3, June 1, 1797. p. 134. “The usual method has been to draw out a fine thread of the soft white glass called crystal, and to convert the extremity of this into a spherule by melting it at the flame of a candle. But this glass contains lead, which

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LIST OF THE PRICES AT WHICH THE MICROSCOPES AND APPARATUS ARE MADE AND SOLD BY MESSRS. JONES, HOLBORN, LONDON.

LIST OF THE PRICES AT WHICH THE MICROSCOPES AND APPARATUS ARE MADE AND SOLD BY MESSRS. JONES, HOLBORN, LONDON.

Magazines of microscopical apparatus, with collections of objects, fitted up to any extent and to order. PLATE 1. Larger Plate Pl. 2A Larger Plate Pl. 2B Larger Plate Plate III. Larger Plate Plate IV. Larger Plate Plate V. Larger Plate Plate VI. Larger Plate Plate 7A. Larger Plate Pl. 7B. Larger Plate Plate VIII. Larger Plate Plate IX. Larger Plate Plate X. Larger Plate Plate XI. Larger Plate Plate XII. Larger Plate Plate XIII. Larger Plate Plate XIV. Larger Plate Plate XV. Larger Plate Plate XV

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Other BOOKS sold by W. and S. JONES.

Other BOOKS sold by W. and S. JONES.

FINIS . London , Dec. 1, 1797 W. and S. Jones take this Opportunity of informing the Public that they have purchased the Stock and Copyright of the several Philosophical Essays by the late Mr. George Adams , of Fleet Street, and that they are now sold at their Shop in Holborn. The following are those now in print, and to be had as above. I. AN ESSAY ON ELECTRICITY, explaining clearly and fuly the principles of that useful Science, describing the various Instruments that have been contrived eithe

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Changes made

Changes made

Footnotes have been moved to under the text to which they belong. Where necessary, page numbers in references to footnotes have been adjusted accordingly. The book uses long dashes as ditto marks; several of these have been replaced with the dittoed text. Where necessary, the word Ibid. in references has been replaced with the actual title. Minor obvious typographical and punctuation errors have been corrected silently. The Errata have already been corrected in the text. Fractions have been stan

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