SCIENCE— ADVERTISEMENTS 



A POTENTIOMETER OUTFIT 



FOR THE MEASUREMENT OF H-ION CONCENTRATIONS, AND OXIDATION, 

 POLARIZATION AND CONTACT POTENTIALS 



A convenient outfit for work of 'moderate accuracy 

 the L. & N. pointer type d'Arsonval Galvanometer. Th 

 J4- millivolt for all voltages which occur in hydrogen el 

 than J/2-miIIivolt, depending upon the resistance of the 

 purposes this accuracy and sensitivity will be sufficient, 

 hydrogen electrode corresponds to approximately %o of 

 coils and cut-out switch and can, therefore, be used a 

 electrolytic conductivities. For the measurement 

 attackable electrode (not included in this outfit) must be 



Tlie components of the outfit, which are sold sep 

 as follows; 



4792. Simplified Potentiometer, L. & N. with ex- 

 tension coils and cut-out switch $90.00 



4S00. d'Arsonval Galvanometer L. & N. 18.00 



8714. Sliding Contact Rheostat, 920 ohms 8.00 



8718. " " " 120 " 8.00 



4826. Eppley Student's Cell 8.00 



4044. Single Contact Key 5.00 



9372. Double Throw Switch, double pole 1.00 



e373. Single Throw Switch, single pole - .65 



s based upon the L. & N. Simplified Potentiometer and 

 ; absolute accuracy of the Simplified Potentiometer is 

 tetrode work. Its sensitivity may be greater or smaller 

 solution containing the hydrogen electrode. For many 

 nasmuch as one millivolt change in potential of the 

 a pH unit. The Potentiometer is supplied with extension 

 i a Kohlrausch slide wire bridge in the measurement of 

 dation or reduction potentials, a platinum or other un- 

 bstituted in place of the hydrogen electrode as shown. 

 arately under their respective catalogue numbers, are 



4844. L. & N. Calomel Electrode Vessel $ 4.50 



4852. Hildebrand Hydi'ogen Electrode 5.75 



48V6. Bent Glass Tube .15 



2090. Burgess Super-six Dry Cells (2) ea. 1.00 



9353. Supports, with chinips and connections 



(2) 



2.85 



Complete Outfit, as above listed, including a sliding contact' rheostat, 120 ohms, in addition to that shown 



in illustration to more readily utilize the full sensitivity of the galvanometer $179.65 



Code Word Ezkyp 



Prices subject to change without notice 



ARTHUR H. THOl 



WHOLESALE. RETAIL AND EXPORT MEHCHANTS 



LABORATORY APPARATUS AI^D REAGENTS 



WEST WASHINGTON SQUARE PWLADELPHIA, U. S. A. 



CABLE ADDRESS. "BALANCE," PHILADELPHIA 



