ii2 TEE POPULAR SCIENCE MONTHLY 



light and electricity, many tests are required on the properties of 

 materials, such as the magnetic properties of iron that is to be used 

 in dynamo-electric machines. All engineering is but applied physics, 

 and a whole building has been devoted to the testing of materials used 

 in engineering and in manufacturing, such as the strength of steel and 

 iron, of concrete, and other materials used in construction, of thread, 

 paper, leather and textile manufactures. It is known that the govern- 

 ment buys all its supplies on specification, and for many of the bureaus 

 the testing is carried on at the Bureau of Standards. In addition the 

 Bureau has two branches, one at Pittsburgh, for testing structural 

 materials, and one at Northampton, Pa., for testing cement, where all 

 the cement used in the Panama Canal is tested. It is easy to see how 

 under this rigid testing many improvements of importance to manu- 

 facturers are developed, and in this way industry is largely promoted. 

 In fact the bureau is now of as much interest to manufacturers and 

 engineers as it is to physicists. 



I have now said enough to show the direct practical importance to 

 the country of a laboratory in which testing, as well as research, is done, 

 even though no teaching is done there. But when I speak of contribu- 

 tions to civilization I do not by any means limit myself to the increase 

 of human comfort, and to the increasing of the production of wealth. 

 Neither do I consider this as the main object of science, nor its chief 

 justification, although it is one that is most easily apprehended by all 

 intellects. Science does not consist in the observation and classification 

 of facts that are useful in this narrow sense, but rather in the fitting of 

 them into a great and harmonious system, that convinces us of the 

 reasonable scheme of nature, and gives us the same esthetic pleasure 

 that the performance of a great piece of music affords, and lifts our 

 spirits to the contemplation of the author of that great scheme of 

 nature, of which, however much we learn, an infinitely greater amount 

 remains for us still to explore. It is only to those who have personally 

 wrestled with nature in the attempt to make her yield up her secrets 

 that this highest aspect of science is revealed. Fortunate are those who, 

 untrammeled by practical ends or the hope of gain, can devote their lives 

 to the calm, undisturbed questioning of nature, and such should our 

 college professors be. It is not yet generally understood that professors 

 should be paid such salaries that they may take this high view of their 

 calling, without being disturbed and in a large degree prevented from 

 fulfilling these highest duties by the struggle for existence. 



I shall now, having described some of the objects and means of 

 research in physical laboratories, attempt briefly to trace the history of 

 one or two notable discoveries of the last quarter of a century, with the 

 results of which at least the public is in a large measure concerned. 

 One hundred years before the present time, almost all that was known of 



