176 Tue Microscope. 
fusel oil and is unaffected by benzole, hence it serves as a 
perfect wall between the benzole of the zine and the soluble 
balsam within. 
After a little experience in mounting the student will have 
no trouble with the old bugbear—the formation of air bubbles. 
One way to avoid their formation is to properly apply the cover. 
The cover glass is held between the thumb and forefinger 
of one hand and applied by its edge near to the margin of the 
preparation. The cover is held in an inclined manner over the 
preparation and beneath the overhanging edge is placed the 
point of a needle. For this purpose the head of a needle should 
be forced into a small wooden handle, or a crochet needle will 
answer; while still better are the needles sold by dealers for 
this and other purposes. By gently lowering the needle the 
cover will gradually come in contact with the preparation, 
driving before it a minute wave of the mounting medium in 
which all air-bubbles are carried off. 
———jq4e>__—_ 
A NEW SOLID WATCH-GLASS. 
C.H. STOWELL. 
E are indebted to Dr. A. Clifford Mercer for specimens of 
W the Syracuse Solid Watch-Glass, a bath, staining or dis- 
secting dish for the histological laboratory and practical micros- 
copists. 
The Syracuse Solid Watch-Glass rests solidly upon the table, 
or microscope stage, and is not liable to be overturned and its 
contents spilled. 
It is transparent and can be used over black, white or 
colored paper, enabling the student to use such back-grounds 
for his work as will permit him to watch its progress to the best 
advantage. 
Transparent tissues can be examined in it from time to 
time or dissected and studied on the microscope stage, while’in 
water, alcohol, oil of cloves, or other bath, enabling the student 
to reject unsatisfactory specimens at any step in the process of 
preparation. 
When the top and bottom edges are cut, one watch-glass 
