376 ANNUAL REPORT 
of water is poured; the material on the outer edge is turned into the 
crater by the aid of a trowel. As soon as the water has been absorbed, 
which should not require more than one minute, the operation is com- 
pleted by vigorously kneading with the hands for an additional 1% 
minutes, the process being similar to that used in kneading dough. A 
sand-glass affords a convenient guide for the time of kneading. During 
the operation of mixing, the hands should be protected by gloves, pref- 
erably of rubber. 
MOLDING. 
59. Having worked the paste or mortar to the proper consistency, 
it is at once placed in the molds by hand. 
60. The committee has been unable to secure satisfactory results 
with the present molding machines; the operation of machine molding 
is very slow, and the present types permit of molding but one briquette at 
a time, and are not practicable with the pastes or mortars herein recom-- 
inended. 
61. Method.—The molds should be filled at once, the materials 
pressed in firmly with the fingers and smoothed off with a trowel without 
ramming ; the material should be heaped up on the upper surface of the 
mold, and, in smoothing off, the trowel should be drawn over the mold 
in such a manner as to exert a moderate pressure on the excess material. 
The mold should be turned over and the operation repeated. 
62. A check upon the uniformity of the mixing and molding is 
afforded by weighing the briquettes just prior to immersion, or upon re- 
moval from the moist closet. Briquettes which vary in weight more than 
3 per cent. from the average should not be tested. 
STORAGE OF THE TEST PIECES. 
63. During the first 24 hours after molding, the test pieces should 
be kept in moist air to prevent them from drying out. 
64. A moist closet or chamber is so easily devised that the use of 
of the damp cloth should be abandoned if possible. Covering the test 
pieces with damp cloth is objectionable, as commonly used, because the 
cloth may dry out unequally, and, in consequence, all the test pieces are 
not maintained under the same condition. Where a moist closet is not 
available, a cloth may be used and kept uniformly wet by immersing the 
ends in water. It should be. kept from. direct contact with the test pieces 
by means of a wire screen or some similar arrangement. 
65. The moist closet consists of a soapstone or slate box, or a metal- 
lined wooden box—the metal lining being covered with felt and this felt 
kept wet. The bottom of the box is so constructed as to hold water, and 
the sides are provided with cleats for holding glass shelves on which _ 
to place the briquettes. Care should be taken to keep the air in the 
closet uniformly moist. 
