Page:Science vol. 5.djvu/496

 SCtENCE.

��[Vol. r.. So. US.

��in excess of what would now be fonnd ; but there is still a distinct preponderance of the right-hand, which, however originoted, has suf- ficed to determine the universal dexterity of the whole historic period.

In the Freuch literary section, Abb(j Tanguay read a statistical paper on the French popula- tion of Canada from 1608 to 1G31.

At the closing general meeting on the 29th, the election of sevei'al new ordinary uaembers was confirmed, and Prof. T. G. Bonney was elected as a corresponding member. Dr. D. Wilson and Eev, T. E. Flainel were elected as president and vice-president for the next meet- ing.

��The recent accident to the steamer City of Berlin emphasizes the importance of devising practical methods of ascertaining the proximity of icebergs in a fog. The precau- tions adopted by Gapt. Laud, though they saved the lives of more than fourteen hundred passengers, and prevented serious damage to the ■vessel, did not prevent contact with the berg. Even the ' look-outs ' were unaware of the proximity of the iceberg until it was actually npon them.

Under these circumstances, the method proposed by Mr. Frank Delia Torre of Baltimore deserves consideration. His experiments in- dicate the possibility of obtaining an echo from an iceberg when in dangerous proximity to a ship. Mr. Delia Torre believes that even an object offering so small a sur- face as a floating wreck may in this way be detected during a fog in time to prevent collision. However this may be, it is ceilAin that his method is worthy of a careful trial at sea, and that preliminary experi- ments, recently made in the pres- ence of Professor Rowland of Johns Hopkins university and the present writer, have demonstrated the fea- sibility of pro<lucing well-marked echoes from sailing - vessels and steamboats at considernhlc dis- tances away.

These experiments were made on the River Patapsco, near the head of Chesapeake Bay, at a point about seven miles from the city of

��Baltimore. The party pi'ocecdcd down the river in a steam-launch to the selected plaoe,. where the distance from shore to shore appeareA^ to be about three miles.

The launch was kept so far from land aa to prevent the possibility of mistaking an echo from the shore for one produced by a passing vessel.

Tbe apparatus employed consisted of a mus- ket to the muzzle of which a speaking-trumpet had been attached (see the illustration). This gun was aimed at passing vessels, while blank cartridges were fired. After a longer or shorter time, according to the distance of the vessel, an echo was returned.

The ordinarj- river- steamboats, and schoon- ers with large sails, returned jrerfectly distinct echoes, even when apparently about a mile distant. At shorter "distances the effects were, of conrse, still more striking.

In order to test the effects under the mo«t disadvantageous circumstances, blank car-

��i

���tridges were flied in tlie direction of an i»p- proaehing tugboat. The surface presented was, of course, much smaller than if the boat

�� �