always place this joint at the side, so that the draughtsman cannot avoid knocking (his nose) against it, or else is obliged to give a very fatiguing inclination to the head. This inconvenience may be avoided by placing the joint not at the side, but at the anterior part of the camera. In addition to this, the axis of movement is vertical, and when the camera is removed from the eye-piece, it is difficult to put it exactly back in the place it occupied, which is, however, very desirable. An axis with horizontal movement would be much better, and by such an arrangement the camera would be raised and lowered on the eye-piece like the cover of a box. Zeiss' Travelling Microscope.-Fig. 6 represents the "Travelling Microscope" of Herr Zeiss, of Jena, which was exhibited at the November meeting of the Society. It consists of the Zeiss stand No. VI., the general construction of which is sufficiently shown by the woodcut; and it packs into a case 8 inches high by 4 inches square. The tube can be readily replaced by a Brücke lens; the stage is hollowed out beneath, and has a concave diaphragm, shown in the foregeing figure, specially adapted to it. The four object-glasses are attached to a revolving "nose-piece," of exceptionally small size, which in packing can be screwed to the foot of the stand. The space beneath the stage is also utilized, in packing, for the Camera Lucida as well as the mirror. The latter is provided with universal movement by an extremely simple and ingenious arrangement. The upper part of the instrument with the stage can be turned round the optic axis. Schöbl's Dissecting Microscope.*-This instrument, which is shown in Fig. 7, consists of a heavy brass base-plate (17 cm. by 12 cm.), on which is supported the stage (22 cm. by 12 cm.) by three uprights, the mirror being attached to one of them. At one of the corners of the stage furthest from the observer is an upright rod 16 cm. high, to which five movable arms of 2 cm. diameter are attached, each arm being capable of being fixed by a screw, as shown in the figure. The lowest carries an aplanatic lens magnifying 30 times; the next, a similar lens, magnifying 15 times, the third, an ordinary dissecting Microscope, magnifying up to 150 *Arch. Mikr. Anat.,' xvii. (1879) p. 165. times; and the fourth and fifth carry two other lenses of low magnifying power (7 and 3 times), the former having a jointed attachment to allow of the lens being placed in any position. The arm carrying the Microscope is ordinarily turned away from the stage to the left of the observer, while the other arms which are not in actual use are placed forwards so as to be out of the way, but are at once available when required. The inventor claims the following as the special advantages of the instrument: (1) The stage is entirely free for work, nothing being in the way of the observer's hands or head on the side at which he stands. (2) It allows of a particularly rapid and convenient change of powers; and (3) The preparation need never be moved from its place during work, and thus a great saving of time is effected. Ward's Improved Microtome.-At the November meeting of the Society, an improved form of microtome was exhibited and described by Mr. F. H. Ward. It is a modification of the one introduced by Stirling, from which, however, it differs in the indicator. The thickness of the section is indicated by means of a screw having thirty-six threads to the inch, to which is attached a wheel containing thirty-five notches upon its circumference; into these notches a spring catch falls in rotation as the screw is turned. This spring is attached to a metal plate through which the screw works, but which is prevented from turning round with the screw by a brass rod fixed into the base of the microtome. The bottom of the well is removable, and is retained in place by two bayonet catches. When removed from its fitting, the bottom is separable into two halves so as to release the screw. The continuity of the thread in the internal screw is maintained in the two halves when in position by means of two metal pegs on the face of one half accurately fitting into holes on the face of the other. The object of this contrivance is, that when the screw has been turned round to its extreme limit, by a slight backward turn the bottom of the well is removed, the two halves separated and the screw is set at liberty, thus: avoiding the wear to the thread and the spring catch, which must. inevitably result from rapidly turning the screw in the reverse direction through about two inches of its length. A thick plate of glass, with an aperture the size of the well, covers the upper brass plate, and slides into position by means of a dovetail on each side. Matthews' Section-cutting Machine.*-Dr. John Matthews has contrived a machine for making sections of such substances as bone, hard wood, ivory, nut, and other materials which are too hard to be cut with the section knife, and not of a nature to require the lapidary's wheel. The carriage holding the saw runs smoothly yet firmly between friction rollers, and derives its reciprocating motion from a crank,. *M. Journ. Sci.,' i. (1879) p. 823. which can be turned either by hand, or, when a higher speed is required, driven by a treadle and pulley. The saw is provided with adjustments to secure its parallelism and proper tension; the section is regulated by a screw of fifty threads to the inch, reading to thousandths by means of a micrometer head; the feed is either automatic by means of a cup, in which a suitable quantity of shot can be placed, acting by gravitation on a lever; or, as Dr. Matthews prefers, is capable of being regulated by hand. Owing to the steady motion of the saw when in proper adjustment, sections of suitable tissues can be cut as thin as the thousandth of an inch; the surfaces show no trace of the saw-cut, and are almost polished; very little after-treatment is needed to remove the few scratches left by the saw, and if required for mounting in balsam it can be done at once, taking the usual precautions to prevent penetration, and the consequent obliteration of structure. Zeiss' Objective.-Colonel Woodward's views on this will be found at p. 988 of the Proceedings.' Micrometry. A reference to this subject will be found at p. 988 of the Proceedings.' BIBLIOGRAPHY OF CURRENT RESEARCHES RELATING TO INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, &c., including Embryology and Histology generally. JOURNALS, TRANSACTIONS, &c., RECEIVED SINCE THE LAST NUMBER, THE CONTENTS OF WHICH ARE INCLUDED IN THE FOLLOWING BIBLIOGRAPHY.* UNITED KINGDOM. England. Annals and Magazine of Natural History, Fifth Series, Vol. IV., Nos. 22-23 (October-November). Entomologist, Vol. XII., Nos. 197-8 (October-November). Entomologist's Monthly November). Magazine, Vol. XVI., Nos. 185-6 (October Geological Magazine, N. S., Dec. II., Vol. VI., Nos. 10-11 (October-November). Journal of Anatomy and Physiology (Humphry), Vol. XIV., Part 1 (October). Journal of Physiology (Foster), Vol. II., No. 3. Midland Naturalist, Vol. II., Nos. 22-23 (October-November). Monthly Journal of Science, Third Series, Vol. I., Nos. 70-1 (OctoberNovember). Naturalist, Vol. V., Nos. 51-2 (October-November). Nature, Vol. XX., Nos. 517*-8*, 519-20, 521*-2*, 523, 524*-5* (September 25-November 20). Popular Science Review, N. S., Vol. III., No. 12* (October). Quarterly Journal of Microscopical Science, N.S., Vol. XIX., No. 76 (October). Zoologist, Third Series, Vol. III., Nos. 34–35 (October-November). London. Entomological Society-Transactions, 1879, Part 2. Geological Society-Quarterly Journal, Vol. XXXV., Parts 3-4, Linnean Society—Journal (Botany), Vol. XVII., No. 103*. 66 Royal Microscopical Society-Journal, Vol. II., Nos. 1-6 (February- Zoological Society-Proceedings, 1879, Part 3 (October). Scotland. Scottish Naturalist, Vol. V., No. 36 (October). Those marked (*) do not contain any article, &c., within the scope of the Bibliography. |