1887.1 Presents. 161 



his fluid condenser and his connecting wire;; he also supports the 

 inner coating of his flnid condenser on ebonite; and, so far as I can 

 discover, fails to take account of the fact that this also would have 

 the effect of diminishing to a small extent the apparent specific in- 

 ductive capacity of the fluid. Possibly this may explain why his 

 results are in all cases lower than mine. Determinations have also 

 been made by Negreano (' Comptes Rendus,' vol. 104, 1887, p. 423) 

 by a method the same as that employed by myself. 



Three substances have been tried with the guard-ring condenser 

 — double extra dense flint-glass, paraffin wax, and rock salt. The 

 first two were not determined with any very great care, as they 

 were only intended to test the convenience of the method. For double 

 extra dense flint-glass a value 9' 5 was found ; the value I found by 

 my old method was 9'896. For paraffin wax 231 was obtained — my 

 previous value being 2'29. In the case of rock salt the sample was 

 very rough, and too small ; the result was a specific inductive capacity 

 of about 18, a higher value than has yet been observed for any sub- 

 stance. It must, however, be received with great reserve, as the 

 sample w r as very unfavourable, and I am not quite sure that conduc- 

 tion in the sample had not something to do with the result. In the 

 experiments with the guard-ring condenser the disturbing effect of 

 the connecting wire was not eliminated. My thanks are due to my 

 pupil, Mr. Wordingham, for his valued help in carrying out the 

 experiments. 



Presents, November 17, 1887. 



Transactions 



Baltimore : — Johns Hopkins University. Circulars. Vol. VI. 

 Nos. 58-9. 4to. Baltimore 1887; Studies from the Biological 

 Laboratory. Vol. IY. Nos. 1-2. 8vo. Baltimore 1887 ; Studies 

 in Historical and Political Science. Fifth Series. Nos. 7-9. 

 8vo. Baltimore 1887 ; Register. 1886-87. 8vo. Baltimore 1887. 



The University. 



Medical and Chirurgical Faculty of the State of Maryland. Trans- 

 actions. Session 89. 8vo. Baltimore 1887. 



The Faculty. 



Peabody Institute. Annual Report, 1887. 8vo. Baltimore. 

 Batavia: — Bataviaasch Genootschap van Kunsten en Weten- 

 schappen. Notulen. DeelXXV. Aflev. 1-2. 8vo. Batavia 1887 ; 

 Tijdschrift voor Indische Taal-, Land- en Volkenkunde. 

 Deel XXXI-XXXII (Aflev. 1). 8vo. Batavia 1887; Dagh- 

 Register gehouden int Casteel Batavia. 1640-1641. Van 

 J. A. Van der Chijs. Large 8vo. Batavia 1887. 



The Society. 

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