SCIENCE— ADVERTISEMENTS 



SPENCER SCIENTIFIC INSTRUMENTS 



Whether MICROSCOPES. MICROTOMES, DELINEASCOPES 

 REFRACTOMETERS OR OTHER SCIENTIFIC APPARATUS 



MAKE AN INSTINCTIVE APPEAL TO THE LABORATORY WORKER 



It isn't only their accuracy and utility. It's 

 something in the finish, even more in the de- 

 sign, but in addition to all these, it is those 

 little things — clever little devices, which ac- 

 complish the same end but in a better way— 

 exactly the way that the laboratory worker 

 wants them. These are the distinctive features 

 of Spencer instruments, made distinctive be- 

 cause our designers, experienced laboratory 

 workers, possess the laboratory view point. 



SPENCER ROTARY 

 MICROTOME No. 820 



The only Rotary Microtome ever made with an incline 

 tlani feed. It overcomes the inaccuracies usually en- 

 SPENCER ROTARY MICROTOME No. 820 ^countered due to the up and down movement of the ob- 



ject. In this microtome the feed and the movement are entirely independent. It has gained an International 

 reputation for perfection and is used by the leading laboratories throughout the world. 



SPENCER LENS COMPANY 



BUFFALO, N. Y. 



THALOFIDE CELL" 



C ( 



A NEW LIGHT REACTIVE RESISTANCE 

 OF GREAT SENSITIVITY 



These new cells will lower their electrical resistance 50 per cent. 



on exposure to .25 of a foot candle when the source used is a 



Tungsten Filament. Special cells are constructed which will do 



this in .06 of a foot candle. 



Their recovery after exposure is extremely rapid as also is 

 their response to the light stimulus which 

 is in marked contrast to the Selenium Cell, 

 especially on exposure to very low light 

 intensities. 



Write for Particulars 



Case Research Laboratory 



AUBURN, NEW YORK 



