MAGNETIC CHARACTERS OF METALS, &c. 631 
its magnetic or non-magnetic condition is an im- 
portant scientific inquiry, which, though for many 
years in the hands of philosophers, remains at 
this day as undetermined as when first under- 
taken. That certain pieces of brass have dis- 
played unequivocal magnetic action is a fact which 
cannot be questioned, but whether that action was 
due to the alloy of pure copper and zinc alone, 
or to portions of iron accidentally present in the 
metal, different opinions have been entertained.* 
“ 9th.—I have likewise often observed, that a long con- 
tinuance of a fire so strong as to be little short of melting hot, 
generally diminishes, and sometimes quite destroys, the pro- 
perty of becoming magnetic in brass. At the same time the 
texture of the metal is considerably altered, becoming what 
some workmen call rotten. From this it appears that the 
property of becoming magnetic in brass by hammering, is 
rather owing to some particular configuration of its parts than 
to the admixture of any iron; which is confirmed still further 
by observing that Dutch plate brass (which is made, not by 
melting the copper, but by keeping it in a strong degree of 
heat whilst surrounded by /apis calaminaries) also possesses 
that property.” 
* During the interesting series of experiments carried on by 
Professor P. Barlow, on the magnetism of ferruginous bodies, 
the brass compass-box, and several brass screws, belonging to 
one of the finest looking instruments employed, were found, 
by that philosopher, to be highly magnetic.—Barlow’s Mag- 
netic Attractions,—Second Edition, P. 17. 
