JOURNAL 
OF THE 
ROYAL MICROSCOPICAL SOCIETY. 
MARCH, 1922. 
TRANSACTIONS OF THE SOCIETY. 
I.— THE MICRO-EXAMINATION OF METALS, 
WITH SPECIAL REFERENCE TO SILVER, GOLD AND 
THE PLATINUM METALS. 
By George Patchin, A.R.S.M., M.I.M.M. 
( Bead November 16, 1921.) 
Two Plates. 
The microscopic examination of metals and alloys is one of the 
recent developments of the Science of Metallurgy with a direct 
application to industry, and whilst it is correct to say that micro- 
scopic metallography has been developed only within the last few 
decades, yet it should be remembered that such examination was 
emploj^ed as far back as the seventeenth century. 
“ Micrographia,” written by Robert Hooke, and published in 
London in 1665, contains, for example, a description of the appear- 
ance of lead as it crystallizes from a lead-silver alloy, and also a 
description of the magnified surface of a piece of polished steel. 
About a hundred years later, namely in 1772, Reaumur applied the 
microscope to the examination of cast irons, but apparently his 
work was connected chiefly with the appearance of fractured 
surfaces. 
Widmanstatten may be said to have laid the first stone of the 
foundation upon which has been built the present methods em- 
ployed for the micro-examination of metals, and as is well known 
he found that some meteorites when cut, polished and suitably 
B 
258 
