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Calcium Chloride in Cement
If from 6 to 10 per cent of calcium chloride is added to cement on mixing when the temperature is below 20 deg. Fahr., not only is freezing prevented, but setting is hastened and increased hardness secured. But such all addition is not safe in reinforced work unless the steel is completely imbedded. In ordinary rendering on metal lathing, there were early signs of bad deterioration of the lathing. (U.S.A., Bureau of Standards)
The Acme Stone Breaker
This machine is well known amongst councils, quarry owners and, in fact, all users of stone-crushers, and, as is generally well known, is a departure from the stereotyped form of Blake crusher, which is supplied by all other first-class makers of such machines. The special nature of this machine is the combination in one part of the two chief moving parts of the Blake type of stonebreaker, thus obtaining a direct action and increased weight and momentum of the operating part which affects the breaking of the stone. The direct action of the machine eliminates unnecessary mechanical complications of levers, toggle plates, connecting rods of the Blake type of power consumption. The direct action results in a sharp crusher, and thereby resulting in economy in upkeep costs and hammer-like blow at the top of the swing jaw where the large pieces of stone are encountered, while there is a secondary finishing and clearing below at the bottom of the mouth, and under equal conditions, than from any other machine on the abling the machine to deal with a larger output, size for site market. The largest movement is at the top of the mouth, where the stone enters the machine, and this enables maximum sizes of stone to be fed into the mouth. In the Blake type of crusher, as made by all other manufacturers, there is very little movement at the top of the mouth, and a simple backward and forward swinging motion at the bottom of the jaws.
THIS specification covers the design of bridges, and is a notable addition to the matter extant upon this subject. It is interesting as there is no other generally-known specification in this country with which to compare it; and it is difficult to find any text books which cover all the points of design called for in this specification, except by having recourse to matter published abroad. The specification appears to be moulded along the lines of the Canadian and American, and to some extent the German specifications, and comparison with these is interesting.