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 hysterical convulsions and chorea are known to spread among girls at boarding-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.
| EXTENSION OF THE SIGNAL SERVICE. |
By Professor JOHN TROWBRIDGE.
THE Signal Service of the United States performs a great service to science by inculcating the value of scientific investigations. Observations in meteorology were 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 pursuits of mankind. He, however, who endeavors to raise money at the present time to equip a physical laboratory in connection with a university, 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 economical 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 inquiring 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 Thomson. "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 satisfaction, 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
