TRESPASS AND INSURANCE 



1157 



In the older fields of geophysical work, namely, magnetic, gravimetric, 

 surface electrical and seismic exploration and electrical well-logging, the 

 early patents have now expired so that it is possible to carry out a great 

 deal of exploration without involvement in questions of patent infringement. 

 Early in the life of each geophysical method there have been issued a few 

 relatively basic patents, followed by a large number of improvement patents 

 as the development of the technique progresses, after which the patentable 

 developments decreased in magnitude. However in any active field there 

 are patentable improvements for many years, usually as long as research 

 is carried on. An example of the growth and decline of the number of 



'30 '34 '38 '42 



TIME IN YEARS 



Fig. 707. 



patents issued in one particular field is shown in Figure 707. It should be 

 recognized that the inevitable time lag between application and issuance 

 of patents makes the peak of the curve fall a number of years after the 

 maximum in the rate of conception of these inventions. The peak shown as 

 occurring in 1941 corresponded to a maximum in patentable inventions 

 four or five years earlier. 



The petroleum industry has long been patent-conscious. Practically 

 everything from jarring tools to cracking processes has been patented. 

 Wherever the traffic would tolerate it, patent royalties would be exacted, 

 as fabulous as the value of the black gold being sought. A royalty of 

 '53%% of the income from rental of patented equipment was not uncom- 

 mon at a time when 10% was high in more sedate industries. 



The rush for patents, and the premium demanded by those successful 

 in obtaining a patent which proved to be a gusher, have excited numerous 

 and hotly-contested infringement suits. The records of testimony taken 

 and briefs written in petroleum patent litigation would constitute a large 



