Nachet, 17 rue St. Severin, Paris
The Nachet-Smith Inverted Chemical Microscope, c. 1885
From John Quekett's A Practical Treatise on the Use of the Microscope, 1852
M. Nachet's Microscope For Chemical Observations.
This very valuable instrument is represented in fig. 265, and is composed of a solid foot, X, in which is fixed the piece, O, for the reception of the small plate, P, on which the objects to be examined are placed; as in this instrument we view the under surface of objects, the illumination must be on their upper surface; for this purpose we fix at pleasure to the piece O the rod T, which holds the mirror, M, and the piece, D, for holding the diaphragms, polarizing aparatus, &c. To the foot, X, is attached a dovetailed slide, V, in which is contained a prism, R, supporting the tube, A, and the body, C. Supposing that a particular object is to be viewed, by means of the two milled heads, B, we draw the prism, R, out of the axis of the instrument, as shown in fig. 266, we screw the object-glass to the piece F, we replace the prism under the small plate, and then adjust the focus by means of the tube A and the fine adjustment, F.
There are in G, fig. 266, two screws, which, coming in contact, prevent R from coming out completely. The office of the prism, R, is to receive the image in a vertical direction, and reflect it to the axis of the body, C, which carries the eye-pieces without any perceptible loss of light. When an object is required to be very much heated, a larger plate, the edges of which are heated by small spirit- lamps, is laid upon the small plate, P. The magnifying powers to be obtained in this microscope vary from 25 to 500 diameters, and all the apparatus necessary for the study of mineralogy can be applied to it, such as the goniometer, micrometer, &c. In short, in the general use of acids, reagents, &c., no injury can happen to the lenses of the object-glasses, as, being placed underneath, they are protected from the oxidizing vapours.
From The Microscope in its Application to Practical Medicine by Lionel Smith Beale, 1858
Microscope for Examining
Substances immersed in Acids and corrosive Fluids.In
examining preparations which require to be immersed in strong acid, in
the ordinary microscope, it is not easy to prevent the fumes from
injuring the brass work of the instrument. Considerable inconvenience
is also experienced in examining fluids while hot, in consequence of
the vapour which rises, condensing on the object- glass, and rendering
the object invisible. These inconveniences are entirely obviated by the
ingenious microscope invented some years ago by Dr. Lawrence Smith, of
Louisville, United States. This was made by M. Nachet, of Paris, and
has been described as Nachet's chemical microscope.*
The description of the microscope from the 1886 Nachet catalog:
This can be translated as follows:
38. - Inverted microscope for
The inverted chemical microscope was first invented by J. Lawrence Smith, professor of chemistry at the University of Louisiana, in 1850. Shortly afterward, the microscope was manufactured by the Nachet firm. The firm continued to produce the microscope, basically unchanged, up to the end of the century. Smith further elaborated on its description in the publication Mineralogy and Chemistry: Original Research, 1873 (this description is essentially identical to the 1852 article referenced above by Beale).
By 1872, two additional inverted models were offered by Nachet
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