35'4 SUMMARY OF CURRENT RESEARCHES RELATING TO 
Walmsley’s “Autograph” Camera, and Walmsley, Fuller, & Co.’s 
Acetylene Gas Generator.* * * § — Mr. C. F. Fox considers that the Walmsley 
“ Autograph ” camera f possesses many advantages with regard to com- 
pactness, steadiness, and general accuracy. It is applicable not only to 
photographing objects through the Microscope, but also to the copying of 
photographs and to the making of lantern slides. 
The best form of illumination with the camera is the acetylene gas 
lamp. Walmsley’s portable apparatus is a modification of the hydrogen 
gas generator. It consists of an outer vessel containing water, and an 
inner vessel open at the bottom and sliding into the outer one. The 
calcium carbide, which on contact with water gives off acetylene, is 
contained in a wire screen or basket placed in the inner vessel. As 
considerable heat is given off in the reaction, the gas, before being led to 
the burner, is cooled and dried by passing through a small chamber 
consisting of one metal cylinder within anothpr, the space between 
the two being filled with cold water. As an illuminant, acetylene 
possesses many advantages : the light is pure and white, and is highly 
actinic ; the temperature of the flame is much lower than in the case 
of coal-gas, and the amount of carbonic acid produced is reported 
to be one-sixth as much, on the basis of candle-power to candle- 
power. 
For use with the Microscope, a lamp which consists of a pin-hole 
burner surrounded by a metal tube lined with plaster of Paris, and 
having a glass slip run into a slot on one side, is very efficient. 
j3. Technique 4 
(1) Collecting- Objects, including: Culture Processes. 
Use of Centrifugal Machines in Zoological Technique^ — Dr. C. J. 
Cori regrets that, although in medical investigations centrifugal machines 
have been long used in order to quickly separate solid material from 
liquids, in zoological methods no general use has been found for such 
apparatus. The cause of this he attributes to the cumbersome and costly 
form of apparatus hitherto employed. This consideration led to the con- 
struction of the simple and cheap centrifugal machine shown in figs. 68 
and 69. The whole arrangement consists of three parts : — (1) the centri- 
fugal machine itself ; (2) the supporting stand ; and (3) a metal cover 
(fig. 69). 
As seen in the figures, the mechanism for rotating the tubes contain- 
ing the preparations is that of the ordinary drill. The rotation is always 
in one direction, for no rotation results from the upward movement of 
the nut T on the spindle Sp. 
* Journ. New York Micr. Soc., xii. (1896) pp. 35-41. 
t See ante, p. 126. 
j This subdivision contains (1) Collecting Objects, including Culture Pro- 
cesses; (2) Preparing Objects ; (3) Cutting, including Imbedding and Microtomes; 
(4) Staining and Injecting ; (5) Mounting, including slides, preservative fluids, &c. f ; 
(6) Miscellaneous. 
§ Zeitscbr. f. wiss. Mikr., xii. (1896) pp. 303-6. 
