94 
time. Treatments at temperatures above 250° C. were carried out by 
heating in covered crucibles in an electric muffie furnace. For lower tem- 
peratures the specimens were immersed in a bath of heated glycerine. 
Sections of the treated specimens were examined and photographed as 
before. A measurement of crystals was made on the ground glass of the 
camera and actual sizes calculated. In the chill cast specimens y-tin- 
antimony crystals varied from 0.015 to 0.05 mm and etin-copper from 0.02 
to 0.18 mm in their longest dimensions. In table I are summarized the 
results of the various thermal treaments of the chilled pieces. Figs. 13 and 
14 illustrate two of the treatments in the lower temperature ranges. 
*All photomicrographs have been reduced one-third by the printer. 
TABLE I 
Tempera- Size of tin-amtimony Sizd of tin-copper 
ture to crystals, millimeters crystals, millimeters 
which Time, ms = — 
reheated, hours . 
degrees C. Upper Lower Upper Lower 
section section section section 
| . 
550 4 0.28 — 0.55 | 0.25 — 0.50 | 0.10 — 2.50 | 0.10 — 2.50 
550 4 0.36 — 0.56 | 0.34 — 0.50 | 0.15 — 2.50 | 0.12 — 2.00 
550 1 0.30 — 0.55 | 0.20 — 0.45 | 0.10 — 1.40 | 0.10 — 2.00 
550 1 0.24 — 0.48 | 0.20 — 0.46 | 0.06 — 1.20 |badly broken 
550 1 0.28 — 0.55 0.20 — 0.46 | 0.10 — 1.60 0.10 — 1.30 
475 ft 0.30 — 0.62 0.20 — 0.48 | 0.04 — 0.40 | 0.04 — 0.40 
475 + | 0.22 — 0.67 | 0.20 — 0.45 | 0.10 — 1.20 | 0.10 — 1.00 
300 1 | 0.20 — 0.40 | 0.12 — 0.30 | 0.03 — 0.60 | 0.02 — 0.22 
300 1 1 0.09 — 0.26 | 0.08 — 0.22 | 0.03 0.41 0.03 — 0.36 
240 2 1 0.06 — 0.18 | 0.03 — 0.12 | 0.04 — 0.21 | 0.03 — 0.18 
230 14% 0.03 -— 0.13 0.03 — 0.09 0.03 — 0.18 0.03 — 0.18 
225 3 0.05 — 0.14 0.04 -— 0.10 0.04 — 0.23 0.03 — 0.20 
220 4 OC: 8Z5—“O EA ohne Shenae ons 0,02 = 0.15.0)... 55 eee 
210 4 O08 — Do aerate eat 0 :015=— 0; 125)... vata eee 
200 6 0208 =O 20s ler eh 8 es 0.02 —.0.H13 |o-6 see 
180 6 OLS —- 0 SObM I Oa ae oe ek | 0.02 — 0.12 |. eee 
166 4 | 0.03 — 0.05 0.015-— 0.035) 0.02 -— 0.17 0.02 — 0.10 
