18 PRESIDENT'S ADDRESS. 



also in connection with manufactures of many sorts, has been 

 repeatedly insisted on during the present war, the advantages 

 which Germany held in many branches of manufacture before 

 the war having been shewn to be due in many instances to 

 Her better appreciation of scientific men and their employment 

 in all her larger works and manufactories. An ingenious 

 apparatus for locating the direction and distances of other 

 vessels in a fog is dependent on the difference of time required 

 by a wireless signal and a sound signal to reach the same 

 point. A series of telephones is placed round the ship, and 

 each is so protected that it will only register sounds coming 

 directly towards it, the direction of the distant ship being 

 thus ascertained. The danger of fire in houses from aircraft 

 attacks has brought to the front the question of fire extin- 

 guishing apparatus, some varieties of which are unreliable 

 and limited in their action, water in buckets being more 

 effective. The occasional failure of tin plugs in boilers to 

 melt when the boilers were overheated has been traced to 

 the presence of zinc which formed a compound only fusible 

 at a much higher temperature. The restrictions on the 

 importation of papermaking material will cause a search for 

 home : grown substances which are suitable, and amongst 

 these straw will probably be used, as it used at one time to 

 be employed to a considerable extent for this purpose. In 

 regard to the very desirable coal economy, peat can be 

 employed to produce gas, and can in this form be used for 

 fuel under conditions in which in its raw state it would not 

 be available, and doubtless many other substitutes will be 

 discovered, necessity being truly the mother of invention. 

 The cinematograph is beginning to be used for advertising 

 machinery, by shewing its actual working on the screen. 

 Submarines have , lately been used for hydrographical 

 purposes, being so arranged that a diver can leave the 

 submarine for the purpose of investigating the bottom of 

 the sea near by. The Kensico dam, a work for the supply of 

 water to New York, has just been completed and has involved 

 the use of 880,000 cubic yards of concrete, the removal of 



