CHEMICAL INDUSTRIES AND RESOURCES 

 deavor of all the factories to have some of their 

 products pass and be entered on this list. Dyna- 

 mite or straight nitroglycerine explosives freeze at 

 a temperature a number of degrees above the freez- 

 ing point of water, and the high explosives fac- 

 tories are now vying with each other in producing 

 "low freezing" high explosives. Great strides have 

 been made in the manufacture of all explosives and 

 a good deal of pioneering in this field has been 

 done on this Coast. The explosives are now built 

 on a much better balance, giving the minimum 

 amount of fumes. They can not only be had in 

 various grades or degrees of strength but also of 

 various speeds or velocity of detonation for the 

 same grade, filling all requirements. 



CEMENT INDUSTRY. California is the third State 

 regarding its output of Portland cement and the 

 productive plants are fairly well scattered all over 

 the State, the locations depending more on trans- 

 portation facilities than the source of raw materials. 

 There is no dearth of lime or clay. For a number 

 of years it was thought that certain constituents of 

 the cement had to be held within very narrow 

 bounds, for instance the magnesia content. There 

 is a chemical ratio for the different ingredients 

 which must not be lost sight of; but experience 

 has shown that a greater latitude may be given to 

 the magnesia content 9f the limestone and that a 

 variety of alumina silicates may be used for the 

 clay. The necessity of burning to a proper clinker 

 has always been recognized, but it has been found 

 that it is essential that the raw materials must DC 

 first ground to an impalpable powder, and of course 

 also the finished product. 



In some parts of the State the cement industry 

 has been threatened with litigation on account of 

 the cement dust nuisance. This nuisance has been 

 abated, the flues lead to a chamber in which are 

 hung a number of iron plates, electrodes. A silent, 

 very high tension electric discharge rids the gases 

 of all solid particles, the dust adheres to the 

 cathode, which is cleaned by a simple device from 

 time to time. The writer nas used the following 

 simple method of judging of the chemical activity 

 of a cement which only requires a pair of letter 

 scales and a few six or eight ounce oil sample cyl- 

 indrical bottles. Weigh off one ounce of cement, 

 put into a bottle and fill the bottle with water which 

 will be in large excess. Shake from time to time and 

 finally note increase in volume of cement. 



LIME AND MAGNESIA. There is an abundance of 

 limestone on the Pacific Slope, and in California 



240 



