SAND-LIME BRICK. 341 
tuff: (1) coarse, containing numerous fragments of pumice and 
andesite; and (2) very fine, containing grains of pumice, feld- 
spar, hornblende, and, at times, a little quartz. Our tests include 
Meycauayan, the best, and Guadalupe, the ordinary volcanic 
tuff. 
TABLE XII.—Volcanic tuff and its efficiency as a sand-lime brick material. 
Content of silica. 
Source. pope in Soluble in 
-_ | sodium Total 
ebleric carbonate! Quartz. silica. 
(Hcl). |NazCOs) 
‘ 
Per cent.| Per cent.| Per cent.| Per cent. 
0.93 20. 45 0.00 59. 72 
0. 02 21. 04 2.08 56. 99 
Degree of pulverization in per cent pass- Compressive 
ing through the specified sieves. Dura- |Molding strength. 
teure| Voleanic oe Pe 
No. pres- | square Per 
No. 20. | No. 40.] No. 80. | No. 100.| No. 200.| sure. | inch. | Total. Baubre 
inch. 
Hours. | Pounds.| Pounds. | Pounds. 
16 | Guadalupe__} 100.0 85.0 70.0 50.0 28.5 5.5 2,300 9,000 | 2,250 
16h eaee dojeeane 100.0 85.0 10.0 60.0 28.5 6.5 4,600 } 10,300 | 2,575 
7h eee dope=== 91.3 71.1 44.4 38.0 25.5 8.0 7,640 | 10,480} 2,620 
ON a ics do -__-.-| 91.3 W.1 44.4 38.0 25.5 8.0} 10,000} 13,640] 8,410 
18 | Meycauayan| 68.5 44.9 28.4 23.5 13.0 8.0 7,640 | 12,440) 3,110 
1b} |e doe= 68.5 44,9 28.4 23.5 13.0 8.0} 10,000} 12,960} 8,240 
HO) eee doves) 70.5 48.3 31.2 26.0 17.8 8.0 7,640 | 18,140] 4,535 
1S) ono dois. 325 70.5 48.3 31.2 26.0 17.8 8.0} 10,000} 20,140 | 5,035 
2.0) Sean domeeses 83.3 61.2 38.2 32.5 20. 2 8.0 4,640 | 20,720) 5,180 
20))| Been do _____- 83.3 61.2 38.2 32.5 20.2 8.0} 10,000 | 22,080} 5,520 
21 | Guadalupe_-_| 100.0 82.6 62.8 55.0 41.0 8.0 7,640 | 14,920) 3,730 
zip | See do =----4 100.0 82.6 62.8 55.0 41.0 8.0} 10,000} 18,280] 4,570 
Molding pres- Density. Absorption after 24 hours in water. 
Mixture | sure in pounds 
No. per square 
inch. Air dry. Dried at 110°. Air dry. Dried at 110°. 
20 7, 640 1.87 1.75 6.0 13.4 
20 10, 000 1.89 1.77 5.9 13.0 
Fig. 1, Plate VI, is a photograph of a 3 by 3 by 2.25-inch 
brick of mixture 18, which was taken after an attempt had 
been made to polish the front surface. A good polish could 
not be obtained, and, otherwise, the natural color was a rather 
unpleasing, dull, light-brown. 
Fig 3, Plate VII, is a photograph of a sand-lime brick made 
