SCIENC 



New Series 

 Vol. L, No. 1290 



Friday, September 19, 1919 



Single Copies, 16 Cts, 

 Annual Subscbiption, i 



LATEST MODIFICATION OF THE McLEOD 

 VACUUM GAUGE 



Vacuum gauges on this principle have been re- 

 peatedly redesigned, each time with a view to cor- 

 recting and simplifying complicated construction 

 and design . These refinements have finally resulted 

 in the Columbia Vacuum Gauge. 



Besides retaining the features of the old McLeod 

 Gauge of 



Ease of reading 



Accuracy (to xo millionth of an atmos- 

 phere) 

 the Columbia Gauge is 



Easier to manipulate 



Simpler | 



Smaller > in construction 



More compact J 



Without ground joints 



SEE OUR EXHIBIT 



AT 



THE CHEMICAL EXPOSITION 



CHICAGO 



SEPTEMBER 22-29 



EIMER & AMEND 



FOUivi»Ei> isni 



Main Offices and Showrooms A-} 

 3d Ave., 18th- 19th Street, New York 



Pittsburgh Branch 

 2011 Jenkins Arcade 



