ANALYSIS IN COMMUNICATION RESEARCH 501 



subject in current journals. Until very recently, however, American 

 chemists did not appear to have fully realized the technical possibilities 

 and advantages of micromethods. The installation of a completely 

 equipped microchemical laboratory at Bell Telephone Laboratories 

 about seven years ago, constituted, the authors believe, a pioneer step 

 in the direct application of microtechnique in its broadest sense to 

 engineering problems. Since that time, a number of industries and 

 industrial institutions have made similar installations with favorable 

 reports as to their usefulness. 



In order to convey a more concrete idea of the types of problems in 

 which the microchemical approach has been particularly helpful at 

 Bell Laboratories, this paper will be concluded with a few actual 

 examples. 



The equipment used in the telephone plant and associated industries 

 contains numerous small functional parts, concerning w^hich analytical 

 information is frequently needed. Such information may be desired 

 in connection with laboratory studies required in the design of the 

 apparatus or it may be needed because of unsatisfactory performance 

 in service, traceable to some irregularity in the particular part. 

 Obviously such results as might be obtained by compositing the large 

 number of parts necessary for an ordinary analysis would be inadequate. 

 Both the peculiarities of the individual case and the variations in 

 quality and composition will be obscured unless the analytical study 

 be made to include only particular specimens. Thus single relay 

 contact points, weighing between five and ten milligrams, have been 

 quantitatively analyzed to check the composition of the alloy when 

 excessive deterioration was noticed. The gold plating, amounting to 

 a few tenths of a milligram, has been precisely determined on small 

 areas of handset transmitter parts for the purpose of observing the 

 uniformity of the coating. 



In studying the various phenomena occurring in vacuum tubes and 

 photocells the Microchemical Laboratory has frequently been requested 

 to identify and occasionally to analyze quantitatively various metallic 

 films and surface deposits in which the total material has ranged from 

 a few thousandths to one or two milligrams. The distribution of 

 caesium on the various surfaces of the photocell was quantitatively 

 studied by microanalysis, the greatest quantity of caesium present in 

 any one determination being about L5 mg. Single filament wires 

 weighing from eight to thirty milligrams have been analyzed, the 

 thoria determined in the case of tungsten filaments, while nickel wires 

 were examined for copper, iron, silicon and manganese. 



Micromethods have been utilized in studying variations in composi- 



