1880. ] Microscopy. 825 
boldt and Ritter were given. He reached Koorlyk, a distance of 
about 180 miles, without difficulty, but had much trouble in 
going on to Dzoon Zassak. The distance from Saisan to Dzoon 
Zassak, at the foot of the Burdan Booda range, is 1370 miles. 
The whole country traversed, with the exception of occasional 
oases, is a desert, and forests were found only on the Tien-Shan. 
Topographical, barometrical and meteorological observations 
have been made, and accurate data obtained for mapping a large 
extent of country, From Dzoon Zassak he started for Lhassa, 
and after being once misled succeeded in crossing the Blue river 
and reaching the Tan-la plateau where a great snowy chain of 
mountains attains a height of 16,800 feet. 
After driving off a party of nomads who attacked them the 
expedition reached its furthest point at the village of Nabchu, 180 
miles from the capital, permission to visit Lhassa being refused 
by the Thibetan authorities. The return journey to Tsaidam in 
the midst of the violent winter storms, was very trying, and took 
two months. Col. Prejevalsky visited Koko-Nor and finally 
arrived at Si-ning on March tgth. He hopes to explore the ` 
upper course of the Yellow river and return home by way of 
: MICROSCOPY.'* 
USE or COLLODION IN CUTTING THIN SECTIONS OF SOFT TISSUES. 
—The preparation to be cut being embedded as usual, collodion 
is applied to the surface of the object by means of a fine brush. 
The collodion is of the regular strength of the United States 
d to settle so as to become as 
Tur Atwoop CeLL.—This new device, intended exclusively for 
mounting opaque objects, was designed by Mr. H. twood, of 
Rochester, and is made in hard rubber by Bausch and Lomb of 
that city. It consists of a black disc, hollowed at the top to con- 
tain the object, and furnished with a rim to receive the cover 
glass. Those now being made are adapted to half inch covers, 
and cost thirty cents a dozen. They can be obtained from the 
1 This department is edited by Dr. R. H. Ward, Troy, N. Y 
VOL, XIV.—NO. XI. 53 
