. .^KJWiAvMr. Daniell on a New liegisler-Pi/rofkeii^i^^ ''•'Ij*^ 



after the accident, it was found necessary to send it to a 

 watclimaker, and when taken to pieces, parts of it were disco- 

 vered to be highly magnetized, the balance-wheel in particular. 

 This was shown to Mr. Faraday, when at Oxford, who set it 

 afloat on a cork, and found the poles to be so well defined, 

 that I have since had it mounted as a compass. Two pair of 

 scissars also that were in Mrs. Boddington's work-box inside 

 the carriage, were by mere accident, two months after the 

 event, discovered to be magnetic. "^'^ 



1 certainly now very much regret that more minute ref- 

 searches were not made at the time as to these facts: but 

 whoever has watched over the sick-bed of a beloved son, with 

 but faint hopes of his recovery, will not be surprised that phi- 

 losophical investigations were all absorbed in the deeper in- 

 terest of the affections. 



Badger Hall, July 16, 1832. 



XLIII. Further Experiments with a new Register-Pyrometer 

 for Measuring the Expansion of Solids. By J. Frederick 

 Daniell, Esq. F.R.S. Professor of Chemistry inKi?ig's Col- 

 lege, London.* 



J N my former communication on a new Register-pyrometer, 

 *- which has been honoured with a place in the Philosophical 

 Transactions for 1830, I stated that I hoped, at some future 

 period, to be able to lay before the Society the results of some 

 experiments upon the dilatation of metals to their melting 

 points ; and I now purpose to redeem this pledge. 



My previous observations upon the subject of expansion, 

 were directed chiefly to the object of establishing what degree 

 of confidence might be reposed in the instrument as a mea- 

 sure of temperature; and I was able, I trust, to exhibit such 

 an accordance between the measures which it had afforded 

 and those of the best experimenters, long previously obtained 

 with various metals to the boiling point of water, as fully to 

 establish its sufficient accuracy. The comparison however 

 which I most relied upon, was with the experiments of MM. 

 Dulong and Petit, upon the expansion of platinum and iron 

 to the high temperature of 572^ Fahr. ; and as this is a point 

 of fundamental importance, I shall still further strengthen it 

 by a comparison with the results obtained by the same distin- 



• From the Philosophical Transactions for 18.31, Part ii.: this paper was 

 read before the Royal Society, on the IGth of June in that year. 



Prof. Daniell's former coinnmnicalion on the same subject will be found 

 in the Phil. Mag. and Annals, vol. x. beginning at p. IKl. 



