28 Mr. Alexander Siemens [Feb. 3, 



several causes have contributed to facilitate the scientific treatment 

 of electrical problems. Not the least among these is the circumstance 

 that at first electricity could not be produced at a cheap rate for 

 general commercial uses. Thus it came about that telegraphy, for 

 which weak currents are sufficient, was for a long time the only 

 practical application, and during this period of comparative quiet a 

 number of the most eminent scientific philosophers devoted their time 

 to discover the characteristic features of this great power in nature, 

 and the laws which it obeys. The consequence has been that at the 

 time when the discovery of the dynamo-electric principle made cheap 

 electricity a possible commodity, the laws on which electric currents 

 act were thoroughly understood, and the development of the intro- 

 duction of electrical appliances could take place on the firm basis of 

 scientific knowledge. 



The obligations that electrical engineers owe to science they have 

 acknowledged in a practical manner in naming the units by which 

 electricity is measured after the learned men who created the science 

 of electricity. 



The circumstance that it is possible to reproduce perfectly the 

 exact conditions for which electrical apparatus have been designed, 

 has much facilitated the direct application of laboratory experiments 

 to practical problems. It is, for instance, quite feasible to take a 

 small quantity of ore, to subject it in a laboratory to chemical and 

 electrical treatment, and to judge from the results whether it will be 

 possible to design works for the treatment of such ores in large 

 quantities on the same lines. As far as electricity is concerned it is 

 possible in such cases to predict with absolute accuracy how much 

 energy is wanted in each case to deposit a given quantity of metal in 

 a given time. The electrical engineer is thus enabled to arrive, in a 

 comparatively easy and inexpensive manner, at reliable data, which in 

 other branches of applied science have to be obtained by costly ex- 

 periments on a large scale. 



One of the most striking instances of the direct application of 

 scientific researches to practical purposes has been furnished by Dr. 

 John Hopkinson, who explained in his lecture before the Institution 

 of Civil Engineers in the year 1883, how he had been led by mathe- 

 matical considerations to infer that alternate-current machines could 

 be run in parallel, and what conditions were necessary to secure 

 success. Ris conclusions were tried shortly afterwards at the South 

 Foreland Lighthouse, and have proved since to be of the utmost 

 value for central electric lighting stations on the alternate-current 

 system. For the sake of historical accuracy I should mention, 

 perhaps, that Dr. John Hopkinson called attention in the following 

 year to a communication to the Royal Society by Mr. Wilde, who 

 bad previously demonstrated the possibility of working alternators in 

 parallel; yet the facts just related are an apt illustration of the 

 point I desired to lay before you. 



While science is a safe guide for the engineer, and will warn him 



