Intelligence and Miscellaneous Articles. 159 
hornblende-andesite, augite-andesite, basalt, and late (if not last) by 
liparite. 
Mr. Topley, who, in the absence of the author, read the paper, 
explained the objects of the Assos expedition and the geological 
results obtained by Mr. Diller. He gave a short account of previous 
literature, and mentioned some of the main points in which oar 
knowledge of the Troad is now advanced. Mr. Topley briefly 
described the physical geography and general structure of the 
country, illustrating this by means of a section which he had pre- 
pared from Mr. Diller's map and paper. 
XXIV. Intelligence and Miscellaneous Articles. 
ON EFFECTS OF RETENTIYENESS IN THE MAGNETIZATION OF 
IKON AND STEEL. 
To the Editors of the Philosophical Magazine and Journal. 
GENTLEMEN, 
TN the April number of your Journal I observe a letter from 
-*- Prof. Warburg showing that a preliminary communication of 
mine to the Royal Society, on the above subject, was in some points 
anticipated by a paper of his, published a year before. I regret 
very much that I have not been sooner acquainted with Prof. War- 
burg's investigations, to which even now I am unable to obtain 
access in Japan. Those of my results which have been previously 
stated by him may therefore be regarded as an independent confir- 
mation of his work. The Preliminary Notice (published in the 
Proceedings of the Eoyal Society, vol. xxxiv. no. 220) refers to no 
more than a small part of an extended investigation of the relations 
of stress, permanent and induced magnetism, magnetizing force, 
and thermoelectric quality (in iron), with which I have been en- 
gaged for three years. I have recently learnt that some of the 
work has been previously done by E. Cohn, and, as it now appears, 
some by Warburg ; and in the full account, which has yet to be 
published, I hope to be able to refer fully to the results of these 
observers, of which my own are in part a rediscovery, in part a 
supplement, and in part entirely independent. 
The University, Tokio, Japan, I hav ®' * c '» 
May 30, 1883. J.A. Ewing. 
ON DRY CHAEGING-PILES. BY JULIUS ELSTER AND 
HANS GEITEL. 
In Zamboni's piles phenomena can be observed which unequivo- 
cally indicate polarization of their plates. If the copper pole of 
such a pile be connected with the positive, and the tin pole with 
the negative discharger of a Holtz machine, the pile, on being 
again disconnected after only a few minutes' action of the machine, 
shows a considerably strengthened tension, which, even after 
