18 CO. BURGE. 



minimum of skin resistance. It is a large subject, with 

 room for great possibilities. 



Akin to friction by water, is the resistance of air. Know- 

 ledge on this has been much advanced by experiments on 

 the Berlin electric express train trials, on the performance 

 of which I was enabled to give the Society some informa- 

 tion in two recent papers. The velocity of the cars, up to 

 130 miles an hour, is the greatest ever reached by any 

 conveyance, and afforded an unusual opportunity of measur- 

 ing air resistance, which was fully availed of. Some of 

 the ocean liners, of the present day, have an exposed cross 

 section of over 3,000 square feet, and, when steaming at 

 23 knots, each pound of air pressure per square foot, on 

 this surface, will absorb over 200 horse power to overcome 

 the resistance offered. The consideration of such facts as 

 these, in connexion with the results obtained on the German 

 train experiments, we may hope will lead to enquiry, as to 

 the best means of coping with this serious impediment to 

 economical speed, on sea and land. 



The dispersion of smoke and fog, neither of which how- 

 ever trouble us much in Australia, is a pressing question 

 in some of the older countries, and electricity has been 

 brought into successful requisition for this purpose, in 

 experimental form. It has been estimated that a bad fog 

 in London may cost £5,000 a day for artificial light alone, 

 so that the importance of this question of the future is 

 undoubted. The difficulty lies in the great quantities of 

 electricity to be applied. 



As regards the change in the physical qualities of metals 

 used for constructive purposes, especially through what is 

 called fatigue, we are looking for more information from 

 physicists. We owe much to the experiments of Wohler 

 and Bauschinger, some years ago, but much remains to be 

 discovered. Railway axles, marine shafts, and other 



