HENRY AND THE TELEGRAPH. 329 



And to the saiae effect let us quote in conclusion .1 few of Henry's urgent utterances. 

 " Every well-established truth is an addition to the sum of human power ; and though 

 it may not find an immediate application to the economy of every-day life, we may 

 safely commit it to the stream of time, in the coulideut anticipation that the world 

 will not fail to realize its beneficial results."* 



" Unfortunately there has always been in England and in this country a tendency 

 to undervalue the advantages of profound thought, and to regard with favor only 

 those investigations which are immediately applicable to the wants of the present 

 hour. But it should be recollected that the scientific principles which at one period 

 appear of no practical value, and are far removed from popular appreciation, at another 

 time in the further development of the subject, become the means of individual pros- 

 perity and of national wealth. "t 



" The progress of society and the increase of the comfort and happiness of the human 

 family depend as a basis on the degree of our knowledge of the laws by which Di- 

 vine wisdom conducts the affairs of the universe. He has created us with rational 

 souls, and endowed us with faculties to comprehend in some measure the modes in 

 which the operations of nature are effected ; and just in proportion to the advance we 

 make by patient and persevering study in the knowledge of those modes or laws, are 

 we enabled to apply the forces of nature to our own use and to avert the dangers to 

 which we are exposed from our ignorance of their varied influences. Nearly all the 

 great inventions which distinguish the present century, are the results immediately 

 or remotely of the application of scientific principles to practical purposes ; and in 

 most cases these applications have been suggested by the student of nature, whose 

 primary object was the discovery of abstract truth. The statement cannot be too 

 often repeated, that each branch of knowledge is connected with every other, and 

 that no light can be gained in regard to one which is not reflected upon all. Thus re- 

 searches which at first sight appear the farthest removed from useful application, are 

 in time found to have an important bearing on the advancement of art, and conse- 

 quently on the progress of society."}: 



" The world generally has failed to recognize the importance of abstract scientific 

 truths. Although these truths constitute the most important elements of modern 

 civilization, since they give man power and control over the inherent forces of nature, 

 and enable him to render these the obedient slaves of his will, — yet there is even at 

 this time, no country (however intelligent it may appear in other respects) that has 

 made adequate provision for the discovery and development of these important princi- 

 ples."^ 



NOTE B. (From p. 273.) 



THE ORIGIX OF THE GALVANOMETER. 



In 1808, Johann Solomon Christian Sehweigger, professor of natural philosophy at 

 Nuremberg, and afterward at Halle, published a memoir '• On the employment of the 

 magnetic force for measuring the electrical." From the somewhat obscure descrip- 

 tion it appears however that the instrument he had devised was simply an " electro- 

 scope" for indicating the static repulsion of ordinary or mechanical electricity; the 

 magnetic needle, armed at each end with a brass button, being mounted on an insu- 

 lated stand or pivot, and used as a substitute for the torsion electrometer of Coulomb. || 

 This arrangement therefore involved no principle of the galvanometer. 



In lail, De la Rive, in a letter to the editors of the ''Bibiiotheque BritanniquCj" 

 recounting some experiments, applied the term "galvanometer" to an instrument for 



* Smithsonian Report for 1856, p. 20. 



+ Agricultural Beport of Commissioner of Patents for 1857, p. 420, 



t Smithsonian Report ftu- 1859, pp. 14, 15. 



§ Smithsonian Report for 1866, p. 16. 



11 Gehlen's Journal fiir die Chemie tmd Physik, Bvo, Berlin, 1808, vol. vii, pp. 206-208. 



