290 Presents. [Jan. 17, 



by sending a current through it ; for this purpose a layer of sul- 

 phuric acid was placed between the primary and secondary coils of 

 such thickness that it almost but not quite stopped the sparks in the 

 latter ; a current of about 2 amperes, which was reversed about 500 

 times a second, was then sent through the sulphuric acid, but the 

 passage of the current did not seem to produce any effect whatever 

 upon the sparks in the secondary. I conclude, therefore that the 

 resistance of an electrolyte is not affected by the passage of a current. 



I wish to express my thanks to my assistant, Mr. E. Everett, for 

 the zeal and skill he has displayed in these experiments. 



[Note added February 15, 1889. I have recently tried the effect of a 

 very high vacuum in stopping the sparks. The primary circuit con- 

 sisted of two straight wires with spheres fastened to one end of each ; 

 these wires were connected with the poles of an induction coil, and 

 the sparks passed between the spheres. The secondary consisted 

 of two similar wires, with smaller balls at the ends, the distance 

 between the balls being very small. The length of the wires of the 

 secondary was altered until it was in resonance with the primary. 

 The secondary was placed in a hollow cylinder formed of two coaxial 

 glass tubes, sealed on to a mercury pump, by means of which a very 

 high vacuum was obtained in the space between them, which sur- 

 rounded the secondary. This vacuum, however, did not produce the 

 slightest effect on the sparks.] 



Presents, January 17, 1889. 

 Transactions. 



Breslau : Schlesische Gesellschaft fiir vaterlandische Cultur. 



Jahresbericht. 1887. 8vo. Breslau 1888. The Society. 



Brisbane: Royal Society of Queensland. Proceedings. Vol. V. 



Parts 1-3. 8vo. Brisbane 1888. The Society. 



Dublin: Royal Irish Academy. Proceedings. Ser. 3. Vol. I. 



No. 1. 8vo. Dublin 1888 ; Transactions. Vol. XXIX. Parts 



3-4. 4to. Dublin 1888. The Academy. 



Edinburgh : Geological Society. Transactions. Vol. V. Part 4. 



8vo. Edinburgh 1888. The Society. 



Falmouth : Royal Cornwall Polytechnic Society. Annual Report, 



1887. 8vo. Falmouth [1888]. The Society. 



Florence : Biblioteca Nazionale Centrale. Bollettino delle Pub- 



blicazioni Italiane. Giugno Dicembre, 1888. 8vo. Firenze. 



The Library. 

 Hermannstadt : Siebenbiirgischer Verein fur Naturwissenschaf ten. 



