228 
SECTION II. 
, (Read December 27th, 1842.) 
48. In the first Section of this Memoir I had 
occasion to allude to the excellent experiments of 
Professor Barlow, on the magnetic action of 
heated iron (11). In the year 1827, I repeated 
those experiments ; and, with the exception of 
a peculiar phenomenon displayed in the Pro- 
fessor’s inquiries, I met with similar results. 
49. At that time I was also engaged in a series 
of inquiries in Electro-Magnetism, especially 
respecting the action of hollow ferruginous mag- 
nets ;* and as I succeeded in producing the same 
degree of deflecting power by hollow as by solid 
pieces of iron of the same form and dimensions, 
when magnetized by electric currents, it occurred 
to me that the magnetic action of iron tubes, at a 
high temperature, presented an exceedingly in- 
teresting problem, which, till then, had never 
been noticed. . 
* Annals of Electricity, &e. Vol. i. p. 472. 
