Reinke's Microscope for observing the Growth of Plants.-J. Reinke, amongst other apparatus for observing the growth of plants, devised the instrument shown in fig. 56. A tripod D supports a hollow pillar S in which slides a second pillar C E which can be raised to a height of 32 cm. from the table and is fixed with a clamp screw. To the latter pillar is attached a horizontal Microscope A focusing by the eye-piece and magnifying about 100 times. In front of the objective B is a glass wheel R 6 cm. in diameter with a grooved edge which runs very easily on two fine steel points let in the bent arm FG shown in the figure. A mirror on a second arm H illuminates the field of view... A thread P passes over the groove in the wheel, the end of which is attached to the plant under examination, and at the other is a weight Q to keep the thread stretched. The circumference of the wheel for 10 cm. is graduated in half millimetres, and each millimetre is numbered. In the body-tube of the Microscope is a micrometer scale with 50 divisions. This is to be adjusted; so that the 0 and 50 of * Bot. Ztg., xxxiv. (1876), pp. 65–9, 91-5, 105-43, 145-60, 169-71 (2 pls.). the scale exactly coincide with two consecutive divisions of the wheel. The half millimetres of the wheel can then be read to 1/50ths (0.01 mm.). As the plant grows the wheel revolves, and the extent of the revolution is read on the wheel and scale by the aid of the Microscope. If the weight reaches the table, the movable pillar can be drawn out, and when the divisions on the 10 cm. of the wheel are passed over it can be brought back to 0 again by gently raising the weight. Tetlow's Toilet-bottle Microscope.-D. Tetlow has patented the following instrument, the specification of which we give verbatim without any attempt at an abstract, venturing only to emphasize one paragraph by italics of our own. The figures are also facsimile. “To all whom it may concern: Be it known that I Daniel Tetlow, of the city and county of Philadelphia, and State of Pennsylvania, have invented a new and useful Improvement in Microscopes, which improvement is fully set forth in the following specification and accompanying drawings, in which Fig. 57 is a perspective view of a Microscope embodying my invention with central vertical sections thereof in line xx. My invention consists of a Microscope having a body of the form of a bottle and the eye-piece removably fitted to the neck thereof, the construction, operation, and advantages being hereinafter set forth. Referring to the drawings, A represents the body of a Microscope, the same being essentially of the form of a glass bottle having a closed bottom which is integral with the body; and B represents the eye-piece, consisting of the lens or glass C and metallic cap or holder D, the lens being properly set in the holder, and the latter removably fitted on the neck of the bottle. E represents a base on which the bottle is stood, the same being formed of metal and receiving the bottom of the bottle, said bottom being shouldered, so as to properly set in the base and provide a neat joint for the parts. While I have described the holder D and base E as metallic, sheet metal being preferred, it is evident that they may be formed of any suitable material and the base may be part of the glass. The eye-piece is removed and an object to be examined placed in the bottle. The eye-piece is then restored, and the object may then be viewed through the lens C, as in Microscopes. The body, being of the form of a bottle, has the following advantages: The object is not liable to be lost or displaced. It may be seen through the wall of the body and comparisons readily made as to its natural and magnified conditions and remain in the body for further examination, as the bottle provides an inclosure, the access to which being the mouth of the bottle, and this is covered by the lens C. Another object of the invention is to employ the body A, primarily, * Specification forming part of U.S.A. Letters Patent No. 287,978, dated November 6, 1883. Application filed August 24, 1883. as a receptacle for some material or substance, such as perfumery. When the body is filled, it is corked and the eye-piece fitted to the neck, an attractive and convenient toilet-bottle thus being produced. The cork is concealed by said eye-piece, so that unauthorized persons will experience some difficulty in abstracting the perfumery. When the FIG. 57. A 1 perfumery is exhausted, the cork is thrown away and the service of the Microscope begins, said service being similar to that hereinbefore stated. To the eye-piece is secured a chain, F, whereby the device may be readily carried, whether as a Microscope or toilet-bottle. Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is 1. A glass bottle having a closed bottom integral with the body thereof and an open mouth, in combination with an eye-piece closing said mouth, formed of a lens and holder therefor, said mouth being adapted to contain a cork, substantially as and for the purpose set forth. 2. A bottle provided with a removable eye-piece and a base and chain, substantially as and for the purpose set forth." Griffith's Multiple Eye-piece.-Mr. E. H. Griffith sends us the eye-piece (fig. 58) which he has devised. A disk at the top of the eye-piece, with projecting milled edge, carries different eye-lenses which by rotation are brought successively into the optic axis. An aperture in the cap shows by a letter which lens is in place. FIG. 58. The upper tube to which the eye-glass disk is attached can be drawn out as shown in the figure, and the lower one, in which the field-lens is set, can be similarly drawn out. Rings marked B and C show the proper position for each power, and when entirely closed, the eye-piece is of the proper length for a D eye-piece. It was intended by the inventor to have a slit with stops for regulating the length of the eye-piece, and that a revolving diaphragmdisk should also be included, but these have not yet been added. As to the utility of the eye-piece, it may be pointed out that whilst it would be very convenient to be able to obtain different eye-piece powers by simply rotating a disk, yet most of the advantage is lost by the necessity of withdrawing the eye-piece from the tube to alter its length-a process which would occupy as long a time as would be required to insert a different eye-piece. Moreover, it is optically impracticable to make use of the same field-lens for B, C, and D eye-pieces. Francotte's Camera Lucida.*-P. Francotte thinks that Beale's camera lucida has a capital defect; the image is formed on the reflector too close to the eye-piece. The consequence is that the whole field is not visible at one time to the eye; whilst, for instance, the centre can be seen, the periphery is invisible; and in order to see all parts of the field, it is necessary to move the eye. Besides this, the short space left free between the eye-piece and the glass is very inconvenient. To obviate this he replaces the eye-piece by a single lens, giving an image which is reflected by an inclined glass plate or a mirror. The inclination of the reflecting surface may vary between 40° and 50°, according to the point of the table upon which the image is to be projected. The image is erect, and the whole field is included. An The apparatus can be easily and very cheaply constructed. ordinary lens (3 to 6 times) in a tube of cardboard is used as the eyepiece. The tube is cut obliquely, so that, on the elliptical section, a thin plate of glass or a mirror may be applied. On the upper surface an opening is made exactly over the place where the image is reflected. By adopting the same principle and replacing the large prism of *Bull. Soc. Belg. Micr., x. (1884) pp. 77-9. Oberhäuser's camera by a mirror, the eye-piece by a single lens, and the small prism by a reflecting glass plate or a mirror, a convenient instrument is obtained which will not necessitate the inclination of the Microscope. Rogers's New Eye-piece Micrometer."-" Professor W. A. Rogers, of Harvard Observatory, has again laid microscopists under obligation by making an eye-piece micrometer for high oculars. It is a coverglass of proper size to fit above the diaphragm of a 1/2 in. or 3/8 in. ocular, ruled in a scale with the fifth and tenth lines longer, and so fine as to need the magnifying power of the eye-lenses to separate the lines well. The high-power ocular separates also the striae of diatoms, or other minute subdivisions of objects, and the scale enables one to count them with a readiness and ease which has not before been possible. It is a simple and inexpensive thing, that takes the place of the most expensive spider-web micrometers." Geneva Co.'s Nose-piece Adapters.-Thury Adapters.-Prof. M. Thury takes exception to the remark at p. 284 that these adapters do not "differ in principle from the nose-pieces of Nachet and Vérick.” The first adapter was, he says, made in October 1863 after his designs for Count Castracane, and another in 1865 for Prof. E. Claparède. A Microscope exhibited by the Geneva Co. at the Paris Exhibition in 1867 was fitted with a similar adapter and was accompanied by a written description. At the 1878 Exhibition the modified movable form was exhibited. M. Nachet, who adopted the fixed form in 1877, "loyally termed it the 'Pince-Thury.' It was after the 1878 Exhibition that the movable form came to be made by others. Prof. Thury's apparatus was evidently therefore the precursor of all such contrivances. Selection of a Series of Objectives.-Several writers have published their views on this subject, differing (with the exception of Dr. Carpenter) more or less from those put forward by Prof. Abbe in his paper on the "Relation of Aperture and Power." Dr. G. E. Blackham † selects "as a set of powers sufficient for all the work of any microscopist the following: = One 4 in. objective of 0.10 N.A. = 12° air angle nearly. The first two to be dry-working objectives without cover correction, the third to be dry-working with cover correction, and the fourth to be a homogeneous-immersion objective with cover correction, and all to be of the highest possible grade of workmanship. The stand to be furnished with six eye-pieces, viz. 2 in., 1 in., and 3/4 in. Huyghenian, and 1/2, 1/3, and 1/4 in. solid. The following table * Amer. Mon. Micr. Journ., v. (1884) p. 52. † Proc. Amer. Soc. Micr., 6th Ann. Meeting, 1883, pp. 33-41, 227-31. |