26 PHYSICAL RESEARCH 



before them ; they have no idea whither they are 

 being led. Were it otherwise research could not 

 be so fascinating. It is in this way that knowledge 

 accumulates, and there is no other way. It is 

 not until it has been acquired that it becomes 

 possible to consider whether or no anything can 

 be done with it. 



It is not usually possible to say: Such and 

 such an invention would be useful or helpful or 

 profitable, let us proceed to make it. An invention 

 is usually an application of some scientific discovery. 

 The applications of science are rightly described as 

 such : and there must be a science to be applied. It 

 may not be the science of the organised laboratory, 

 though as a matter of fact it usually is in these 

 days. It may be no more than the scientific obser- 

 vation of some keen mind which notices, reflects, 

 associates and draws conclusions. But whatever 

 the actual source of development, there really has 

 been some knowledge on which to build. We 

 may well set this down as one important principle 

 and proceed to add two more. 



A second may be stated in the form that know- 

 ledge is not generally acquired for the purpose of 

 making any particular invention. The course of 

 advance is in the main beyond human control. 

 Those who conduct research into the laws of nature 

 know well that their progress is made where it can 

 be made. When the thread of an intricate skein 

 is followed and disentangled, one must follow the 



