82 BULLETIN" 1216, U. S. DEPARTMENT OF AGRICULTURE. 
cient for immersing the test pieces if a 200 cubic centimeter beaker 
is used. The same portion of hydrochloric acid may be used for at 
least five test pieces. Five cubic centimeters of the antimony 
chloride solution, however, should be added for each sample on 
account of the antimony being removed from the solution by the 
iron. The difference in weight in grams, divided by 3 (number 
of pieces taken) is equal to the coating in ounces per square foot. 
Cashman's 3. (i>) Cushmari's method. — The determination of the weight of 
method. spelter coating by this method is based upon the action of hydro- 
chloric acid upon the galvanized coating, collecting and measuring 
the hydrogen gas evolved." The weight of coating may be de- 
termined upon flat sheets, corrugated sheets, and formed culverts, 
by the use of differently shaped rings provided with the apparatus. 
The coating upon wire can be determined by placing a definite 
length of wire under the flat ring on a glass plate. 
4. The metallic rings are made of nickel, tinned iron, or other 
acid-resisting metal, and are fitted with No. 12, three-hole rubber 
stoppers. Through one hole passes the filling tube provided with 
glass stopcock. Through the other holes pass the exit tubes, the 
short tube to a position even with the bottom of the stopper, the 
long tube extending to a position even with the bottom of the ring. 
A measuring burette and leveling bottle are provided for collect- 
ing and measuring the hydrogen evolved. 
5. The measuring burette is first filled with water, allowing a 
small amount of water in the leveling bottle. The proper ring is 
selected for the culvert to be tested, and is placed upon the culvert 
and sealed with " Plasteline," or other acid-resisting wax. The 
stopcock on the acid tube is turned so as to communicate with the 
short tube and is then connected with the measuring burette by 
means of a rubber tube. Water is now placed in the filling tube, 
the stopcock opened, and the ring and connecting tubes com- 
pletely filled with water by lowering the leveling bottle and 
allowing the air to flow into the burette. By means of the three- 
way stopcock on the measuring burette, it is again filled with 
water without disturbing the water in the ring. 
6. The stopcocks in the measuring burette are opened and the 
stopcock on the exit tube turned to connect the long tube with 
the burette. If there are any leaks-in the apparatus, the water 
in the measuring burette will fall. With everything prepared and 
ready, about 30 cubic centimeters of concentrated hydrochloric 
acid are placed in the filling tube and about 5 cubic centimeters 
admitted to the ring. The hydrogen generated from the zinc will 
force out the water in the ring. As soon as gas appears in the 
long exit tube, the stopcock is quickly reversed to the short exit 
tube. 3 cubic centimeters of antimony chloride solution 18 are 
added to the acid in the filling tube, and the acid allowed to run 
into the ring. 
7. When the generation of gas has ceased, the ring and con- 
necting tube are completely filled with water through the filling 
tube by lowering the leveling bottle, and as soon as the liquid 
reaches* the burette the stopcock is turned off, the water in the 
leveling bottle and burette brought to the same level, and the 
volume of hydrogen recorded. 
8. The burette stopcock is now turned to communicate with the 
waste beaker and enough water passed through the ring by means 
of the filling tube to remove all acid. By turning the stopcock 
to the long exit tube the ring can be completely drained. In case 
the ring is lower than the burette stopcock, it is necessary to 
blow out the water with a rubber tube and stopper inserted in the 
filling tube. The ring can then be removed and the spot on the 
culvert cleaned with gasoline. The spot may then be coated with 
a paste of zinc powder and zinc chloride (50 per cent solution) 
17 The apparatus for making this test can be obtained from the Kauff- 
man-Lattimer Co., Columbus, Ohio. 
1S Five grams of antimony chloride dissolved in 1.00 cubic centimeters of 
concentrated hydrochloric- acid, specific gravity 1.20. 
