SCIENCE— ADVERTISEMENTS 



Development and Progress and Improvement of Labora- 

 tory Instruments have led us to develop 



a new school type of 

 ALTERNATING CURRENT METER 



Highest Grade of Laboratory Ap- 



pciratus and Supplies for 



all Laboratories 



Agriculture, Biology, Physics, Chem- 

 istry, Physiography, Physical 

 Geography 



CATALOGS SENT UPON REQUEST 



A — Agricultural Apparatus and Supplies. 



B — Biological Apparatus and Supplies. 



C — Chemicals, Minerals and Soils. 



G — Physics and Chemistry Apparatus and 

 Supplies. 



D — Diplomas for Grade Schools, High 

 Schools, etc. 



4 — Loose Leaf Notebooks, Papers, Her- 

 bariums, Manuals, etc. 

 5C — General School Supplies. 



L — Lantern Slides, Microscopic slides and 

 Balopticons. 



The enthusiastic reception and the splendid performance of 

 the Welch Direct Current Meters of Commercial Quality, but 

 designed especially for schools has led to the development of a 

 new Alternating Current Meter of Commercial Grade for school 

 laboratories. 



We are pleased to announce quantity production and 

 a consequent price reduction in Welch alternating current 

 meters. 



Some of the special features and characteristics of the 

 new Welch Alternating Current Meters are mentioned 

 below. Complete bulletin describing in detail the superior 

 qualities of these instruments, will be sent upon request. 



The Case is dust tight and handsomely finished. 



The Pointer is of light aluminum tubing. 



The Zero Corrector is provided for setting the pointer. 



Dead Beat action is obtained by carefully constructed 

 damping device. 



The Accuracy is guaranteed to one half of one percent 

 of full scale. 



The Scale is almost uniform, about 90 percent of the 

 scale is large enough so that it may be guaranteed in 

 full. 

 Write for full description, list of ranges in stock and price. 



qA Sign of ^ality 



qA Mark of Service 



W. M. WELCH SCIENTIFIC COMPANY 



Manufacturers, Importers and Exporters of 

 Scientific Apparatus and School Supplies 



CHICAGO, ILL., U. S. A. 



1516 Orleans Street 



