SCIENCE— ADVERTISEMENTS 



lU 



Satisfaction of the 

 Convincing 



IS 



TYPE K POTENTIOMETER OUTFIT as used in pj^ measurements, with two 

 Clark type of hydrogen electrodes and accessory glasszvare mounted on 

 motor-driven shaking device. See Chapters XI and XII of Clark's J' The Determi- 

 nation of Hydrogen Ions". 



The uniformly successful and satisfactory operation of the Type K 

 Potentiometer with its accessories for Hydrogen Ion Measurements 

 has made it a valued and important part of the equipment of many 

 laboratories carrying on scientific investigations or controlling pro- 

 duction processes. 



" Electrometric Methods and Apparatus for Determining Hydrogen 

 Ion Concentrations" — Leeds & Northrup Catalogue S75 — ^will help 

 you determine whether the Type K Outfit is adapted to your work, 

 or whether some other combination of instruments w^ould serve as 

 well. 



If your work leads you into problems of acidity or alkalinity determi- 

 nations, or of making accurate titrations under difficult conditions, a 

 reading of Catalogue S75 may mean time well spent. We shall be 

 glad to furnish the catalogue. 



LEEDS & NORTHRUP COMPANY 



Electrical Measuring Instruments 

 4901 Stenton Avenue PHILADELPHIA, PA. 



