16 JUNE 1883, Page 23

The Conservation. of Solar Energy. By C. William Siemens, F.R.S.

(Macmillan and Co.)—Mr. Siemens publishes here, together with the original paper, read to the Royal Society last year, the correspondence which that paper, with the remarkable theory which it stated, called forth, in Nature and the Comptes Rendus. The subject was well threshed-out, and no one will doubt the benefit of having all the argument preserved in this convenient form. •