460 



SCIENCE. 



[Vol. V., No. 122. 



in excess of what would now be found ; but 

 there is still a distinct preponderance of the 

 right-hand, which, however originated, has suf- 

 ficed to determine the universal dexterity of 

 the whole historic period. 



In the French literary section, Abbe Tanguay 

 read a statistical paper on the French popula- 

 tion of Canada from 1608 to 1631. 



At the closing general meeting on the 29th, 

 the election of several new ordinaiy members 

 was confirmed, and Prof. T. G-. Bonney was 

 elected as a corresponding member. Dr. D. 

 Wilson and Rev. T. E. Hamel were elected as 

 president and vice-president for the next meet- 

 ing. 



PREVENTING COLLISIONS WITH ICE- 

 BERGS IN A FOG. 



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 Capt. 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 

 upon them. 



Under these circumstances, the 

 method proposed by Mr. Frank 

 Delia Torre of Baltimore deserves 

 consideration. His experiments in- 

 dicate the possibilit} T 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 ma}'- be, it is certain 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 producing well-marked __ == _ 

 echoes from sailing-vessels and — % 

 steamboats at considerable 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 proceeded down the 

 river in a steam-launch to the selected place, 

 where the distance from shore to shore appeared 

 to be about three miles. 



The launch was kept so far from land as to 

 prevent the possibility of mistaking an echo 

 from the shore for one produced by a passing 

 vessel. 



The 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 ordinary river- steamboats, and schoon- 

 ers with large sails, returned perfectly distinct 

 echoes, even when apparently about a mile 

 distant. At shorter distances the effects were, 

 of course, still more striking. 



In order to test the effects under the most 

 disadvantageous circumstances, blank car- 



tridges were fired in the direction of an ap- 

 proaching tugboat. The surface presented 

 was, of course, much smaller than if the boat 



