SCIENCE— ADVERTISEMENTS 



No. 274S-G 



A New 



A New Type and New Ranges of the Dodge Rheostat, Designeil by Homer L. Dodge, 

 University of Oklsjioma. 



In order to avoid the difficulties incurred with the ordinary sliding-contact form of rheostat, this 

 type of rheostat has been designed so that by the operation of a switch, the load may be connected in 

 a series or in a multiple connection with the rheostat or a portion of it. This makes it possible to 

 secure very small currents with a shunt or potentiometer connection. It also makes it possible to se- 

 cure large currents with a series connection. This insures a universal application for sliding-contact 

 form of rheostat. By properly making the connections for this rheostat with a switch mounted on 

 the base makes possible a connection which may be changed from series to multiple by simply throwing 

 a switch. This avoids the necessity of the student making a change in connections and the possibility 

 of having them wrong. 



This new form of rheostat is constructed on standard and proven lines with many special points 

 of superiority. Jt is practically all metal — only the base and the rubber at the -top of the slider are 

 non-metallic. 



The Rheostat is complete with binding post and switch as shown, so that by operating the 

 switch the load may be changed from a series connection to a multiple or a potentiometer connection. 



These special features of the Dodge Design Rheostats make them much more useful than the 

 ordinary design, and they may be used for experimental work of many different kinds. 



Non-corrosive resistance wire with practically zero temperature co-efficient is used for winding 

 this rheostat and this wire is wound on an enameled steel tube. 



Handsome in finish, sturdily built, and furnished in the ranges listed below. 



90 65 40 20 10 5 



Approximate Resistance, 

 Current Carrying Capacity, 



Ohms 3000 500 175 

 Amperes 0.5 i 1.5 



A SIGN OF QUALITY 



■?■ - ^ G.UALITY ^-Y't I ■ ■ ., ■ 



\yy]g.!L(Cj]][ A MARK OF SERVICE 



1516 Orleans 



Manafactarers, Importers and Exporters of 



ScienSiSc ApparaSws and School Sappiiss 



Street 



CHICAGO^ ILL., U. S. A. 



