JOURNAL OF BACTERIOLOGY 



AN OUTFIT FOR THE 



PRECISE ELECTROMETRIC DETERMINATION 



OF H-ION CONCENTRATION IN SOLUTIONS 



THE TEST 

 m OUR STOCK FOR IMMEDIATE SHIPMENT 



OF SERVICE 



4882 

 Type K Potentiometer Outfit, 'with'diagrammatic illustration of'connections. 



This equipment is suited for practically every hydrogen-ion research problem in bacteri- 

 ology, physiology, and bio-chemistry, and has been arranged as a result of the experience of 

 many competent investigators in this field. It is parlicularly convenient as regards setting 

 up and operation since no adjustments requiring high manipulative skill are necessary. The 

 Clark hydrogen electrode is perhaps the most widely used for biological solutions. With the 

 Enclosed Lamp and Scale Galvanometer as above illustrated, the type K Potentiometer 

 Outfit measures the diiference in potential between a calomel electrode and hydrogen elec- 

 trode to from .02 to .04% (± .2 millivolts), which in ordinary solutions is the "equivalent of 

 0.0001 of the pH unit. The outfit consists of the following equipment. 



4790.'«Type K Potentiometer, L. & N 275.00 



4796.IFTSnclosed Lamp and Scale Galva- 



Jnometer, L. & N 55.00 



4797. Lamp Resistance for Galvanometer, 



for no volts 5.00 



4878. Combined Support and Shaker, 



IL. & N. for calomel electrode, con- 



E"necting vessel and hydrogen electrode, 

 with motor 75.00 



4820. 

 2092. 



4854. 



48M. 

 4866. 

 9374. 



Weston Standard Cell, Model 4 25.00 



Storage Battery 6.00 



Clark Hydrogen Electrode Vessels 

 with two platinum electrodes for same 



(2) ea. 9.00 



Calomel Electrode Vessel 4.00 



Clark Connecting Vessel 7.80 



Switch, single pole double throw 80 



4882 Complete Outfit, as above listed, with Shaker with motor for 110 Word 



volts, 60 cycle a.c 471.60 Ezimq 



4883. ditto, but with [Shaker with motor for 110 volt d.c 471.60 Ezjef 



Prices subject to change without notice. 



ARTHUR H. THOMAS COMPANY 



WHOLESALE, RETAIL AND EXPORT MERCHANTS 



LABORATORY APPARATUS AND REAGENTS 



WEST WASHINGTON SQUARE PHILADELPHIA, U.S. A. 



Cable Address, "BALANCE," Philadelphia 



