628 EXPERIMENTAL INVESTIGATION OF THE 
the talent and expedients that have been em- 
ployed in the pursuit, little or nothing has been 
satisfactorily ascertained beyond that which is so 
conspicuously displayed by those two metals,— 
iron and nickel. (7—13.) 
5. There is something very remarkable, how- 
ever, respecting the magnetism of these two dis- 
tinguished metals when in combination with other 
bodies. Nickel, for instance, is said to lose all 
its magnetic action when combined with even a 
small dose of arsenic, and iron has long been un- 
derstood to suffer the same fate when alloyed 
with antimony. Beyond these two alloys of 
nickel and iron, I am not aware that any other 
have been magnetically investigated, although, as 
will appear in the sequel, some of the most ex- 
traordinary facts that have hitherto appeared in 
the magnetism of metallic bodies, are displayed 
by alloys of iron with other metals.* 
6. Tiberius Cavallo was amongst the earliest 
inquirers into the magnetic action of non-ferru- 
* At the time this first part of the Memoir was read, I was 
not aware of these curious and interesting facts. They were 
subsequently discovered, and are described in the second part. 
