5© 



written a history of magneto and dynamo machines. We 

 worked most harmoniously together, and there was very little 

 tendency to national partizanship. 



The Classes reported their judgments to their respective 

 Groups, and the results were finally revised by the whole jury. 

 The number of gold medals awarded was 79 ; of silver, about 

 150; and of bronze, about 250. The highest distinction of all, 

 not counting the complimentary awards to governments and 

 societies, was the Diploma of Honor given to inventors. Of 

 these there were only 11, which were awarded to Sir Wm. 

 Thomson, Dr. Werner Siemens, Professor Hughes, M. Gaston 

 Plante, Mr. Edison, Professor Graham Bell, M. Gramme, Pro- 

 fessor Pacinotti, Professor Bjerknes of Christiania, M. Marcel 

 Depretz, and M. Baudot. Most of these names will be well known 

 to you, but the last three or four are probably unfamiliar. M. 

 Baudot is the inventor of a very elaborate method of sending 

 several telegrams at once, and making them print themselves 

 in Roman letters. M. Marcel Depretz has paid great attention 

 to the theory of the distribution of electricity, and was the 

 organiser of a large proportion of the electrically driven appa- 

 ratus in the Exhibition. Professor Bjerknes was the exhibitor 

 of some very striking experiments on mutual attractions and 

 repulsions between vibrating bodies immersed in a liquid. He 

 had little drums, with indian rubber ends, which were made to 

 bulge out and draw in with rapid alternation by means of 

 quick-acting pumps which alternately forced air in and with- 

 drew it several times in a second. The little drums, being 

 immersed in water, attracted one another when their phases of 

 vibration were similar, and repelled when they were opposite. 

 He had many other experiments on the same subject, the action 

 in some being directive rather than attractive or repulsive. 

 The connection between these experiments and electricity con- 

 sisted in an analogy which they were supposed to bear to 

 electricity and magnetic actions. They were supposed, indeed, 

 to throw some light on the nature of electricity. They were 

 certainly very suggestive. 



Some of you will remember the name of Pacinotti in con- 





