EXTENSION OF THE SIGNAL SERVICE. 507 



vomiting, which may be caused by the recollection of disgusting sights 

 or odors. The principle of imitation accounts for the rest. The great 

 nervous centers, in multitudes of people, being in a state of polarity, 

 any unusual exhibition of feeling would throw the more excitable into 

 spasms ; and the affection would then spread by sympathy, as hyster- 

 ical convulsions and chorea are known to spread among girls at board- 

 ing-schools. And, as fear has checked these, the epidemic convulsions 

 were checked by reason and common-sense, and finally ceased under 

 the law which limits all violent action. Brain. 



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EXTENSION OF THE SIGNAL SERVICE. 



By Professor JOHN TROWBEIDGE. 



THE Signal Service of the United States performs a great service 

 to science by inculcating the value of scientific investigations. 

 Observations in meteorology wei'e formerly buried in the proceedings 

 of learned societies, and met the eyes only of a few scientific men : 

 now they are discussed at the breakfast-tables of a million people. 

 The departments of physics in our universities and technical schools 

 have reason to thank the Signal Service for leading the public mind 

 to see the importance of physical investigations to the ordinary pur- 

 suits of mankind. He, however, who endeavors to raise money at the 

 present time to equip a physical laboratory in connection with a uni- 

 versity, will find that the Signal Service still has work to do among 

 the practical business-men of this country men whose successful 

 prosecution of their commercial enterprises depends upon the econom- 

 ical use of steam, upon careful scientific consideration of atmospheric 

 changes, conditions of heat' and moisture, and sanitary laws. There 

 are men of this class who accept what they call progress, without in- 

 quiring into the causes of it, and who have never thought of physics as 

 a science to which business is indebted for its successful prosecution. 

 " What is meant by the word physics ? " asks the man who consults 

 the paper to discover if the storm-center which has been developed in 

 Texas, and whose progress has been telegraphed, will probably strike 

 his steamship, which is off Cape Hatteras. This steamship has recently 

 been fitted up with the most approved compound engines, which have 

 been perfected by the labors of those physicists, Rankine and Thom- 

 son. " What is meant by the word physics ? " asks the manufacturer, 

 with a telephone to his ear, listening to a response from his factory. 

 The solicitor for the endowment of a physical laboratory has the satis- 

 faction, even if he fails to obtain a subscription, of feeling that he is a 

 public educator. 



It is very probable that any plan for the extension of the Signal 



