Reichert's Polarization Microscope.-This (fig. 55) is an inexpensive form of stand by C. Reichert, the chief peculiarity of which is that the wheel of diaphragms with five apertures rotates at the end of a horizontal arm, which, as with the condenser in the preceding form, swings on a pivot away from the stage, as shown in the figure. The diaphragm-plate is raised above the arm on a vertical axis, so that the tube attached to the largest aperture to hold the polarizer

may not prevent the complete rotation of the plate. A notched projection on the arm falls against a second spindle beneath the stage when the apertures of the diaphragm-plate are central. The tube which holds the polarizer has a rotating fitting, and carries the polarizer with it.

The analyser fits over the eye-piece without any attachment, which would seem to be undesirable, even though the Microscope can only be used in an upright position.

When the polarizer is in place the plate cannot rotate completely, but no rotation is then required.

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 CE 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

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.