388 British Association for the Advancement of Science. 



two; that for hydrogen of four ; that for carbonic oxide of three ; 

 that for carbonic acid of three; and that for nitrous oxide of two 

 experiments. 



A bare inspection of this table would seem to justify the conclusion 

 that, with a single exception, the different gases operated with have, 

 under equal volumes, specific heats proportional to their specific gra- 

 vities ; and of course that, under equal weights, they have the same 

 specific heat. In the excepted case, that of hydrogen, the specific 

 heat is nearly the double of that which would result from this law. 



On the absence of Magnetism in Cast Iron when infusion. By 

 R. W. Fox. 



In the course of some magnetic experiments, it appeared to the 

 author desirable to ascertain whether a magnetic needle is acted 

 upon by cast iron in a state of fusion. For this purpose he had a 

 horizontal mould made in sand, about five feet long and two inches 

 square, in the direction of the magnetic meridian ; and at a very 

 small distance from its northern extremity, and parallel to it, he 

 placed the south pole of a delicately poised magnetic needle, the 

 north pole of which extended beyond the mould. The latter was 

 then filled with very fluid melted iron, but not the slightest effect 

 was produced on the needle till after the metal had become fixed 

 and cooled down to a cherry-red colour. The needle was then very 

 suddenly attracted with great energy. Sand and a copper plate 

 were employed to protect it from the hot iron. 



This experiment may perhaps be considered by those who advo- 

 cate the existence of a high temperature in the interior of the earth, 

 as tending to strengthen the arguments in favour of the agency of 

 electricity in producing terrestrial magnetism, seeing that intense 

 heat and fixed magnetism, in the ordinary acceptation of the term, 

 cannot, apparently, exist together.* 



On Electric Currents passing through Platinum Wire. By William 

 Barker, M.D. 

 When the large deflagrating battery was used on two occasions 



• [Mr. Peter Barlow had shown, many years since, that all magnetic ac- 

 tion was lost by iron when raised to a white heat ; from which the inference 

 above drawn by Mr. Fox has, we believe, been deduced by other men of 

 science ; but we are not aware that the experiment was ever tried before 

 with iron in a state of fusion. See Phil. Trans. 1822, or Phil. Mag., first 

 geries, vol. Jx. p. 345. — Edit.] 



