CONSTKUCTIOIsr AK"D FIKE PROTECTION" OF COTTON" WAREHOUSES. 63 
CHEMICAL EXTINGUISHERS. 
Chemical extinguishers are of two general types. One contains 
a reservoir of water with chemicals so arranged that, when the ex- 
tinguisher is inverted, the chemicals produce a reaction with result- 
ing pressure which is capable of discharging the water with consid- 
erable force. The other type of extinguisher generates a gas which 
clings about the fire and does not support combustion. While both 
types of extinguishers are of value in some cases, neither of them 
should be depended upon for the cotton warehouse or compress, as 
water barrels and pails are more satisfactory particularly where ig- 
norant labor is employed. There is possibly some advantage in hav- 
ing one 2^-gallon extinguisher at the compress tower. 
YARD HYDRANT SYSTEM. 
An adequate system of yard hydrants fully equipped and main- 
tained is one of the greatest assets of a warehouse plant. Unfor- 
tunately, the value of the yard hydrant installation is often impaired 
because the hydrants are not located properly or because the equip- 
ment has deteriorated. Hydrants should be housed with all equip- 
ment ready for use as shown in figure 7. 
heavier solution and the purpose of the treatment will be defeated. The data 
given for calcium chloride is based upon the chemically fused product generally 
used for refrigeration purposes. The tables are adapted from those given in 
Van Nostrand's Chemical Annual. 
Treatment of water with sodium chloride, or common salt. 
Sodium chloride per gallon solution. 
Freezing point. 
Fahrenheit. Centigrade 
Specific 
gravity 
at 59° F., 
15° C. 
Weight of 
solution 
per 
gallon. 
Density 
at 59° F.. 
15° C 
0.44 pound, or 7 ounces 
0.9 pound, or 15 ounces 
1.22 pounds, or 1 pound 4 ounces. 
1.92 pounds, or 1 pound 15 ounces 
2.5 pounds, or 2 pounds 8 ounces.. 
+25.4 
+18.6 
+12.2 
+ 6.9 
+ 1.0 
-3.7 
- 7.4 
-11.0 
-13.9 
-17.2 
1.037 
1.073 
1.1115 
1.150 
1.191 
9.0 
9.3 
9.6 
9.9 
°B. 
5.2 
9.9 
14.5 
19.0 
23.3 
Treatment of water with calcium chloride (fused 75 per cent CaCh). 
Amount calcium chloride per gallon of solu- 
Freezing point. 
Specific 
gravity 
at 68° F., 
20° C. 
Weight of 
solution 
per 
gallon. 
Density 
at 68° F\, 
20° C. 
tion. 
Fahrenheit. 
Centigrade. 
o 
+ 18.0 
+ 12.5 
+ 6.5 
- 2.0 
-12.5 
o 
- 7.8 
-10.8 
-14.2 
-18.9 
-24.7 
1.1 
1.125 
1.15 
1.175 
1.2 
9.2 
9.4 
9.6 
9.8 
10.0 
13.0 
16.0 
19.0 
2.59 pounds, or 2 pounds 10 ounces 
21.3 
24.0 
