432 
ON THE STRUCTURE OF METALS, 
Description of Plates 9 and 10. 
Number 
of 
micro - 
section. 
Description of specimen. 
Gold alloyed with 
Treatment of the 
0'2 per cent, of 
alloy. 
Zirconium .... 
Poured in a mould . 
Lithium. 
55 55 
Indium. 
5 5 5 5 
Aluminium . . . 
55 5 5 
Potassium .... 
5 5 5 5 
Zirconium .... 
55 55 
Bismuth .... 
f Annealed at about 1 
\ 200° to 250° / 
Antimony .... 
Rhodium .... 
55 ^ 55 
Poured in a mould . 
Nothing (pure gold) 
Potassium .... 
5 5 55 
Rhodium .... 
Aluminium 
Indium. 
Thallium .... 
Nothing (pure gold) 
Indium. 
55 55 
Indium. 
Thallium .... 
f Annealed at about *1 
\ 200° to 250° J 
I Bismuth .... 
Bismuth .... 
Antimony .... 
55 5 5 
1 
Reagent 
by which the 
section 
was etched. 
Aqua regia 
55 
y> 
55 
55 
Sulphuric acid 
Aqua regia 
Nitric acid 
Aqua regia 
Method ' , 
0 f Lnlarge- 
• i ment, 
niumma- 1 
tion. 
Oblique 
Normal 
linear. 
17 
17 
17 
17 
17 
17 
17 
17 
1000 
1000 
150 
150 
150 
150 
150 
150 
500 
150 
150 
150 
1000 
150 
Notes. 
Photograph No. 1 would represent equally well either gold alloyed with Bi, Rh, Zn, Pd, Tl, or pure 
gold prepared under the same conditions. 
Photograph No. 2 would also represent gold alloyed with Se, and poured in a mould; while No. 3 
would represent gold alloyed with antimony. 
Photograph No. 11 shows a mixture of grains and crystallites, a secondary crystallization belonging 
to classes 0 to 3 with thick crystalline joints. 
Photograph No. 12 presents a characteristic case in Avhich crystallites are absent; there is no second¬ 
ary crystallization, and there are very fine non-crystalline joints. 
Photograph No. 13 shows the complete development of secondary crystallization, with variable and 
disconnected joints. 
Photographs Nos. 14 and 17 show the intermediate stages of secondary crystallization, the joints being 
thick and crystalline. 
Photograph No. 15 shows a very thick joint crossing a paste of primary crystallization. 
Photograph No. 16 shows the general aspect of joints, which would be traced by sulphuric acid on 
most of the specimens. 
Neither these photographs (11 to 17) nor photographs 1 to 6, 9, 10, and 21 are characteristic only of the 
alloys from which they were taken; they have been chosen as typical illustrations of the organization 
of primary crystallization, of the variable development of joints, and, in fact, of the general phenomena 
which have been described in the text. 
Photographs 7, 8, 19, 20, and 22 are of a more special nature; they show the effects of annealing at a 
given temperature on a given alloy. 
