16 PRESIDENT'S ADDRESS. 



ENGINEERING. 



Aeroplanes have been so much used in the present war, 

 that much must have been learnt about them by practical 

 experiment, but any knowledge acquired in this or other 

 ways would necessarily be kept carefully secret. They seem to 

 have become much more stable than formerly, and can be ussd 

 in ways which would have been impossible a few years ago . 

 There is still, however, much room for improvements. We 

 have fortunately had an opportunity of studying at leisure 

 the make of the Zeppelins brought down during the raids. 

 These enormous airships, some 680 feet long, can hardly be 

 said to have proved a success in war, and, considering their 

 cost, have done but little actual damage, though for " fright- 

 fulness " they take a high rank. With regard to sea-ships, 

 it has been attempted to construct one of concrete with steel 

 framing, but I do not know whether it has met with much 

 success. Barges have been made of this material and have 

 been regularly used, but it would seem unsuitable for a large 

 ship. A bridge over a river has lately been completed on the 

 Great Central Railway, having a Scherzar rolling -lift opening 

 span, weighing 2,900 tons, probably the largest in the world, 

 giving an open waterway 150 feet wide. It can be opened 

 or closed in 3 minutes by two electric motors of 115 hoise 

 power each. A new and very valuable article of equipment 

 in the war is the helmet now worn by our troops. It is 

 made of steel, and, with its inside padding of felt and wadding 

 with rubber studs, weighs 21bs. An exhibition of glass, 

 held at Sheffield last December, called attention to the great 

 development of glass making, especially glass for optical 

 and other scientific purposes, in this country, since the 

 beginning of the war. Much of this was previously imported 

 from Germany, but we shall in future be able to supply 

 ourselves with this important article. British sands have 

 been discovered which are nearly if not quite equal to that 

 from Fontainebleau for glass making for all except optical 

 glass. In view of the scarcity and the restrictions on the 



