97 



square incli, should be chosen ; though such as have bubbles or 

 scratches near the ends will not look ornamental in a cabinet, we 

 should remember that microscopic objects are not generally 

 mounted to look well in a cabinet, but to be useful out of it, so 

 that if the central and useful portion of the slide be perfect it 

 need not be rejected. Thin glass, such as is made on purpose 

 for microscopic use, will be next required, and it will be found 

 more convenient to buy it ready cut into squares and circles than 

 to attempt to cut it ourselves. If, however, we do have to cut it 

 ourselves, we may follow the direction given in the books, which 

 I will not repeat here, only adding one fact that I have not seen 

 generally noted, which is to place the thin glass on a piece of wet 

 thick glass, or marble, the water preventing its breaking, as it will 

 be apt to do if this precaution be not taken. The thin glass may 

 be of different thicknesses, but for the more dehcate species it 

 must be as thin as possible. It should be perfectly clean, which 

 may be insured by removing the grease with potassa lye, and the 

 resinous substances with turpentine, or alcohol, or both. The 

 thinner kinds of glass are rather difficult to clean, but with a little 

 extra caution this may be accomplished, the last polish being 

 given to it by a piece of old and well worn cambric. It should 

 then be separated into thicknesses and kept in starch powder, 

 which prevents its being scratched, but all the starch must be 

 carefully removed with a dry piece of cambric before the glass 

 be used, otherwise granules of starch will be introduced which 

 will prove puzzling when we come to examine the slide under the 

 microscope. 



We shall also require a pair of forceps for holding the slides 

 over the spirit lamp, and such as are sold under the name of 

 American clothes-pegs are extremely useful, and answer all the 

 purposes of more complicated and expensive arrangements. A 

 small pair of brass forceps which close with a spring will be 

 needed for holding the thin glass, and an ordinary pair which 

 spring open, and may be closed by means of the finger and 

 thumb, will be wanted for removing the thin glass from the box 

 in which it is kept. A spirit lamp holding about four fluid 

 ounces and a few test tubes for boiling the deposits, together with 

 a small quantity of nitric acid, alcohol, and turpentine, will be 

 found necessary. For the purpose of making cells will be needed 



PROCEEDINGS B. S. N. H. VOL. VII. 7 SEPTEMBER, 1859. 



