236 PECULIARITIES IN THE MAGNETISM 
64. The experiments with the hollow iron, 
(51—62,) are, I believe, the only ones of the 
kind hitherto made. They are interesting on two 
accounts. They show that the magnetism of 
hollow iron bars at high temperatures, observes 
the same laws as solid bars of the same dimen- 
sions, when similarly treated; and they also show 
that the extent of magnetic action, under these 
circumstances, is precisely the same both in hol- 
low and solid iron. This latter fact is in strict 
accordance with the results obtained by the action 
of cold iron, as shown by another interesting 
series of Mr. Barlow’s experiments.* 
65. During the time that one of the solid bars 
remained neutral, it occurred to me that there 
still existed a possibility of some slight magnetic 
action being present which could not be detected 
by the needle at the distance of six inches. I 
therefore caused the hot bar to be placed with its 
upper end at the distance of three inches from the 
needle, but still no magnetic effect was produced ; 
nor do I think that any magnetic action would be 
detected even though the needle were placed close 
to the heated bar. . 
* Barlow’s Magnetic Attractions. 
