VARLEY'-NACHET. 
these tables are made with a plate-glass top, and surrounded by 
drawers, in which the apparatus can be conveniently assorted. 
MR. VARLEY’S MICROSCOPE. 
87. This artist has constructed instruments with provisions 
similar to those already described; they are somewhat different in 
their form and details. He has, however, recently introduced a 
microscope, which claims the advantage of enabling the observer to 
examine living objects, such as animalcules, notwithstanding the 
inconvenience arising from their restless mobility, causing them 
continually to escape from the field of view. The stage motion 
with its appendages, contrived by Mr. Yarley, enables the 
observer, without difficulty, to pursue the object. 
He has also contrived a phial-microscope, by which aquatic 
plants and animals can be conveniently observed. 
m. cachet’s microscopes. 
88. M. Nachet, of Paris, has acquired an European celebrity for 
the excellence of his instruments, and for the various inventions 
and improvements in their construction, by which he has extended 
their utility. He has constructed instruments in various forms, 
according to the uses to which they are to be applied and their 
price. For medical and chemical purposes, the body of the 
microscope slides in a vertical tube, the coarse adjustment being 
made by a rack and pinion, and the fine by a screw. The stage 
is firmly fixed under the object-piece, at the top of a hollow 
cylinder, within which the illuminating apparatus and other 
appendages are included. 
89. One of the most recent novelties due to this eminent artist, 
is a form of microscope by which two or more observers may, at 
the same time, view the same object, thus conferring upon the 
common microscope a part of the advantages which attend the 
solar microscope. This is accomplished by connecting two or 
more tubes, each containing its own eye-piece, with a single tube 
containing an object-piece; it has been already shown that the 
axis of the tube containing the eye-piece may be placed at any 
desired inclination, with that which contains the object-piece, by 
placing in the angle formed by the two tubes, a reflector, or 
reflecting prism, in such a position, that the pencils of rays pro¬ 
ceeding from the object-piece shall be reflected to the eye-piece, 
without otherwise deranging them. It is evident, therefore, that 
if the rays proceeding from the object-piece could be at the 
same time received by two or more reflectors, so placed as to 
reflect them in two or more directions, they might be transmitted 
along two or more tubes in these directions to two or more eye¬ 
pieces, through which the same object might thus be viewed at 
