SCIENCE-ADVERTISEMENTS 



111 



A New Electrically Heated 

 Constant Temperature 



Water Bath for Serologic Work 



Write for Pamphlet 



PAL9 COMPANY 



Laboratory Supplies and Chemicals 



90-94 Maiden Lane, New York City 



Handy 

 Resistance Units 



Single value spools mounted in 

 blocks of hard wood of convenient 

 size and shape. Blocks for all values 

 are uniform in size. 



Each unit will carry a load of 2 

 watts and is guaranteed to be accu- 

 rate to within 1/20 of one per cent, 

 at the temperature of adjustment. 



Prices are very reasonable. 



They are described and listed in Cir- 

 cular No. 3, which will be sent on 

 request. 



Pyrolectric Instrument Co, 



Pyrometric and Electrical Precision 

 Instruments 



148 E. State St. 



E. F. Northiup, President « 



Trenton, N. J. 



id Technical Adviser 



a 



Jagabi " Laboratory Rheostats 



"We illustrate a new style of Sliding-Contact Rheostat, as invented and patented by Prof. 

 H. L. Dodge, of Iowa State University. 



A '' Dodge Design " Rheostat may be used on the voltage for which it is rated, with a load of 

 any resistance— and is always capable of providing any current value in the load, between zero and 

 highest rating of the rheostat. Consequently the maximum range of regulation is available ; and 

 the selection of a suitable rheostat is greatly simplified — for the line voltage, together with maxi- 

 mum current rating, are the only characteristics that need be considered. 



The above, and other types of " Jagabi" Laboratory Rheostats, are illustrated and described in 

 Bulletin SS7. Write for copy to-day. 



JAMES G. BIDDLE, 1211-13 arch st., Philadelphia 



