6 Transactions. — Miscellaneous. 



Full efficiency also can only be obtained wben full power is 

 being exerted. At half and quarter speeds the loss of effi- 

 ciency is very great, and as yet the efficiency is at best very 

 considerably below that of the average ordinary marine engine 

 of the day. But in this turbine the long-sought realisation of 

 a successful rotary engine has been attained. 



In electrical engineering we have the third great branch of 

 the profession; and it is one which, in its far-reaching 

 ramifications, already exceeds the most diversified practice of 

 the conventional civil engineer or his brother of the marine. 

 To draw a contrast between electrical engineering fifty years 

 ago and to-day would indeed be comparing small things 

 with great. The electrical engineer as known to us now had 

 no existence in those days. Electricity was employed, we 

 may say, in only two works of commercial importance — those 

 of electroplating and telegraphy. The original patents for 

 both of these applications were overridden by what was called 

 "magnetic plating" and the "magnetic telegraph." Per- 

 manent magnets were used in both cases, and it was not 

 until it was found that electro-magnets could be substituted 

 that the phenomenal advance in the science and practice of 

 electricity took place. To speak in detail of the evolution of 

 the electrical engineer is not my purpose. My endeavour 

 is to interest you, not to weary you if I can avoid it ; 

 but I may mention one circumstance which stands out 

 boldly in my memory in the light of present experience. 

 My worthy old friend the rector of the Scots Gram- 

 mar School aforesaid, in his lectures on electricity, held 

 it to be impossible that the electric light should be 

 commercially successful. His reasoning was based on the 

 difference between the atomic weights of carbon and zinc. 

 At that time this was given as 6 to 32, now more ac- 

 curately stated as 11-97 to 64-9, but the ratios are very 

 nearly the same. Had the electric light been possible of 

 production only by the primary battery, in which zinc is 

 the fuel, the old gentleman would have been right, for 

 1 ton of coal, or rather of carbon, would go as far in 

 chemical combination as more than 5 tons of zinc. But the 

 invention of the dynamo gave coal its opportunity; and yet 

 it is at a heavy disadvantage, in so far as it cannot be 

 applied directly in a primary battery like zinc, but must be 

 used through the intervention of the steam or gas engine. 

 Now, the steam-engine is the most wasteful of prime movers, 

 so far as the conversion of the thermodynamic value of fuel 

 into work is concerned. It has an efficiency of only from 10 

 to 12 per cent., and very seldom reaches 15 per cent., while 

 the efficiency of the primary battery may be averaged at 

 90 per cent, or more. If, therefore, carbon could be used 



