SCIENCE— ADVERTISEMENTS 



Highest Grade of Laboratory Ap- 

 paratus 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. 

 DC — Electric Meters, direct or alternating 



current. 

 W — Wireless Apparatus and Supplies. 

 Lists of apparatus for state requirements 

 and for text books. 



Ask for list for your state or for your text. 

 Manuals, on physics, physical geography 

 and agriculture. 



Samples sent for examination upon request. 



qA Sign of ^ality 



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. 



OUR POLICY 



To attain the highest possible standard of service 

 is the purpose which dominates all other considera- 

 tions in the designing and building of "WELCH" 

 Laboratory Apparatus and Supplies. 



qA Mark of Service 



W. M. WELCH SCIENTIFIC COMPANY 



1516 Orleans Street 



Manufacturers, Importers and Exporters of 

 Scientific Apparatus and School Supplies 



CHICAGO, ILL. 



