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CASES OF MICROSCOPIC OBJECTS; ROBERT'S TRACINGS 02s GLASS. [Claes X.
Frame 4.
1. Adulterated milk, magnified 1,200 diameters.
2. Calf’s brains, magnified 1,200 diameters.
3. Milk with linseed tea, magnified 1,200 diameters.
Frame 5.
1. Human bone, a thin transverse section of the cla-vicle, magnified 95 diameters.
Small portion of ditto, magnified 440 diameters.
2. Ostrich bone, transverse section, magnified 95 dia-me-crs.
Small portion, magnified 440 diameters.
3 . Turtle bone, transverse section, magnified 95 dia-meters.
Small portion, magnified 440 diameters.
4 . Hoof of horse, trausvcrse section, magnified 95 dia-meters.
Small portion, magnified 440 diameters.
Frame G.
1 . Lepidostcus scale, transverse section, magnified 95diameters.
Small portion ditto, magnified 440 diameters.
2. Sword-fish, transverse section of the sword, mag-nified 95 diameters.
Small portion ditto, magnified 440 diameters.
3. Spine of Ray, from which shagreen is made, mag-nified 95 diameters.
Small portion, magnified 440 diameters.
4. Human lung (healthy) injected, magnified 150 dia-meters.
5. Human lung (with tubercles) injected, magnified150 diameters.
These anatomical and microscopical drawings deservevery Honourable Mention : the whole of their outlinesand proportions have been executed by means of the ca-mera lucida, so that they represent truly what the eyeactually sees, and the details are finished with scrupulousaccuracy ; they are, therefore, among the most trust-worthy representations of minute and elaborate tissuesthat perhaps have ever been executed.
Topping (No. 667, p. 467*) exhibits five cases of mi-croscopic objects. The contents of the first case are,—test objects adapted to the present state of microscopicscience, ranging from two inches power up to one-twelfthof an inch of large aperture; also some of the most beau-tiful of the fossil infusoria.
Case 2--Contains fossil aud recent vegetable structures.
Case 3—Dissections of insects. In this case are largedissections of the respiratory systems of the silkworm,caterpillar, and larvae of beetles: all these are mountedin Canadian balsam.
Case 4—Sections of fossil teeth, bones, and shells, &c.In this case there is a diamond showing woody structure,and sections of oriental and Scotch pearls.
Case 5—Contains injected animal tissues.
Mr. Topping has mounted the greater part of theseobjects in Canada balsam : lie remarks that this is theonly medium whicli will permanently preserve specimensof natural history as objects for the ’microscope, and thatlie uses chrome yellow, instead of vermillion, for injec-tions, with which material lie can inject the minutestcapillaries.
Mr. Topping’s methods of mounting and preservingobjects, are many of them of his own invention; Jie de-serves to be distinguished above other exhibitors, as hewas one of the first in the field, and perseveringly over-came many difficulties which others following after hadnot to encounter. Ilis anatomical injections are admir-able, as are also those of Hett (Xo. 249, p. 435), but inthis branch neither of them is an original inventor, butare followers of John Queckett, Esq., of the Royal Col-lege of Surgeons . A Prize Medal was awarded to Mr.Topping.
Bourgogne (France , Xo. 434, p. 1199) has exhibited ,a case of microscopic objects prepared in the usual man- jner. They are mounted in Canada balsam, and consist jof sections of wood, and entomological and other prepara-
tions, with a selection of salts to illustrate the polarizationof light. The objects are well displayed, and carefullymounted. A Prize Medal was voted to M. Bourgogne.
Xobert (Prussia, No. 77, p. 1053), of Barth, has exhi-bited his wonderful tracings on glass. The plan adoptedby him is to trace ou glass ten separate bands at equaldistance from each other, each band being composed ofparallel lines of some fraction of a Prussian inch apart,iu some they are TAgth, and in others only a-Lth of aPrussian inch sepaJated. ’ ^
The distance of these parallel lines form parts cf ageometric series; thus—
0-001000 line.
0-000857 „
0*000735 „
0*000630 „
0*000540 „
0*000463 „
0-000397 „
0*000340 „
0-000292 „
0-000225 „
To see these lines at all it is necessary to use a micro-scope with a magnifying power of 100 diameters; thebands containing the fewest number of lines •will then bevisible. To distinguish the finer lines it will be neces-sary to use magnifying power of 2,000, and then the lineswhicli are only of an inch apart will be seen as
perfectly traced as the coarser lines. Of all the tests yetfound for object-glasses of high power these would seemto be the most valuable. These tracings have tended toconfirm the undulating theory of light, the differentcolours of the spectrum being exhibited in the ruledspaces according to the separation of the lines; and inthose cases where the distances between the lines aresmaller than the lengths of the violet light waves, nocolour is perceived; and it is stated that if inequalitiesamounting to *000002 line occur in some of the systems,stripes of another colour would appear in them.* APrize Medal was awarded to Mr. Xobert.
Lkndy (Sardinia , GO, p. 1304) has exhibited severaldies or minute copies on silver and steel, of various de-vices. These specimens of minute and excellent work-manship are produced by a machine invented, but notexhibited, by Mr. Lendy. By its means any model,however elaborate, varying in size from 7*87 inches to0’039 inch in diameter, may be reduced to one-fifteenthof its original size, a degree of minuteness which rendersthe copies so reduced almost imperceptible to the nakedeye. On subjecting them, however, to examination bythe microscope, they are found to be composed of linesof all but unparalleled delicacy and distinctness.
Mr. Lendy, who has been for many years engraver tothe Royal Mint at Turin , has originated this ingeniousinvention, for the use of banks, mints, goldsmiths’ com-panies, &c-., with a view to the avoidance of counterfeits.We may particularize the following dies or puncheonswhich are exhibited:—
A royal crown engraved on silver, and very elaborate,the lines within side being so fine, that a common haircovered five of them. The same design in relievo is alsoexhibited.
A ducal crown engraved on silver, and surrounded bya gothic frieze, executed with sharpness and precisionnever before equalled in so minute an object. The samedesign in relievo is also exhibited.
A coat of arms containing a gothic “ R,” surroundedby a gothic frieze, and engraved on steel, 0*013 inch indiameter: in its execution it is as graceful as distinct. Asimilar design in relievo is also exhibited.
Another ducal crown on steel, equally good with thepreceding, is exhibited, as also one in relievo.
Upon steel a copy of Mr. W. W yon’s medal (the de-sign of which is a portrait of Her Majesty, surroundedwith the words Victoria, D.G. Britanniarum ReginaF.D.), it is 0*06 inch in diameter, the original being
* See Poggendorff’s “ Annalen ” for 1846, and “ Pro-ceedings of the Royal Society,” April 10, 185L