National Resources Planning Board, Industrial Research 



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developed before there were physicists or the profession 

 to which they belong. Nevertheless the work of the 

 inventors and of those who developed these devices was 

 physics. They have beconae such an integral part of 

 our civilization that it is difficult to imagine life without 

 them. 



The Steam Engine 



It is difficult also to unagme modern civilization 

 without some of the more recent developments in which 

 the organized science of physics played a part. The 

 early steam engine of Newcomen was very inefficient m 

 transforniing heat energy into mechanical energy and 

 could hardly have become very significant industriafiy. 

 James Watt realized that much more energy would be 

 available if it were possible to let the steam expand in 

 the cylinder before it was allowed to escape. As a 

 result of this simple consideration, the steam engine 

 became so much more efficient that it developed mto a 

 practical device. Because of its convenience as a source 

 of power it contributed in large measure to the uidustrial 

 revolution then m progress. The importance of the 

 steam engine in ocean, river, and railway transportation, 

 and in the production of electric power, gives evidence 

 of the major role that physics has played in the develop- 

 ment of modern industry. 



Dynamo-electric Machines 



Similar illustrations may be taken from other fields. 

 The two physicists, Faraday in England and Henry in 

 this country, began a series of purely scientific experi- 

 ments which led to the dynamo-electric machines of 

 today. These machines have made possible electrically 

 powered transportation on both land and sea, electrical 

 ilhunination that allows us to carry on practically all 

 our activities at night as well as in daylight, and power 

 for all types of electrical communication. The develop- 

 ment not only of the elementary dynamo-electric 

 machines themselves, but of their practical forms and of 

 the systems making practical use of them, has been an 

 accomplishment of physics and physicists. 



Applications of Light 



In the field of light we have illustrations of a some- 

 what different natm-e. Modern artificial illumination 

 has been made possible as a result not only of the 

 development of the dynamo-electric machines that 

 supply the power, but also as a result of the develop- 

 ment of light sources themselves. The step-by-step 

 improvement of the incandescent lamp, which will be 

 discussed later, with its rapidly increasing efficiency 

 and decreasing cost, has resulted from the application 

 of fundamental physical principles. 



Many other applications of the science of light occur 

 in industry. In ferrous and nonfcrrous metallurgy, 

 the methods of spectroscopic analysis have become 

 indispensable. These methods are based upon the fact 

 that light can be separated into its component colors. 

 When the source of light is a metal vaporized in an arc 

 the colors can be separatetl still fuilher into discrete 

 lines characteristic of individual chemical elements. 

 By spectroscopic analysis it has been possible to detect 

 impurities in alloys and in supposedly pure metals and 

 even to determine quantitatively the amount of these 

 impurities. The importance of this method of analysis 

 can be understood only by a full realization of the effect 

 of small quantities of impurities on metallic systems and 

 the occasional resultant failures of those systems. 

 Spectroscopy has made possible the accurate, quick, and 

 efficient analyses that are necessary for the control of 

 furnace charges and for the control of alloy compositions. 



In another type of analysis the invisible longer wave 

 length portion of the spectrum is of use in studying 

 absorption to determine very quickly some of the 

 groupings in organic compounds. By this method it is 

 possible to determine, for instance, the state or the 

 condition of the oils used in paint vehicles, or of various 

 types of gums or of lubricants, without having to 

 decompose the organic compounds and try to put them 

 through an ordinary chemical analysis, which is a very 

 difficult and a long process. Stiidy of progressive 

 changes in organic compounds by this method is of 

 enormous importance, as can be realized when one 

 remembers the many organic materials that have 

 become commercially useful in the last few years, as, 

 for instance, plastic materials, of which there are at 

 present hundreds to choose from, with all sorts of 

 characteristics, and paint veliicles which change gradu- 

 ally upon exposure to increased temperature, variable 

 humidity, or sunlight. The ability to follow the 

 transformations in the formation and aging of such 

 compounds provides an indication according to which 

 the chemist can direct his course. Apparatus used for 

 this purpose may be made to draw a curve which the 

 operator soon learns to recognize, since distinctive 

 shapes are caused by the presence of definite groups of 

 atoms. 



A very mteresting recent application illustrates the 

 way in which physics has invaded the field that was 

 formerly reserved for the chemist. In the analyses for 

 gaseous impurities, such as carbon dioxide in the air 

 that we breathe, or of poisonous gases, it has been found 

 possible by physical means to determine in a few seconds 

 the quantity of an impurity in any sample of air even if 

 present to the extent of only one part in a million. 

 The analysis may be made continuously with permanent 

 records. The apparatus is selective and can be ar- 

 ranged to read the amount of carbon monoxide, of 



