540 JOURNAL OF CHEMICAL EDUCATION MARCH, 1929

"TheLaws of Patentsfor Useful Inventions" (3 Vols.), by W. C. Robinson, Little, Brown & Co., Boston, Mass., 1890.

"Patent Essentials for the Executive, Engineer, Lawyer and Inventors," by J. F. Robb, Funk & Wagnalls Co., N. Y., 1928.

British Practice

"Patents and Chemical Research," by H. E. Potts, University Press of Livcrpool, 1921.

"The Law and Practice Relating to Letters Patent for Inventions" (7th ed.), by Thomas Terrell, Sweet & Maxwell, London, 1927.

Protecting Foundations against Acid Attack. While the ordinary concrete floor is long-lived and wear-resisting in most types of factory, it is readily susceptible to chemical attack and disintegration when used in places where there is constant exposure to acid. Thus the foundations of a building may also he attacked in time. A type of flooring is needed which can resist unavoidable spilling of acid and can also withstand heavy loads and hard wear. Such properties are claimed for Prodorite, a compound far flooring, which has remarkable resistance to acid attack. It h a s according to a National Physics Laboratory report, a crushing strength of 6000 lb. per sq. inch, and possesses s resistance to abrasion double that of matured 2 : l sand-Portland cement concrete. At 60-C. the material is stated to withstand concentrated hydrochloric acid, 65 per cent sulfuric acid. and 15 per cent nitric acid. I t also resists the above acids in the cold at greater concentration. A Prodorite floor is composed of precast slabs bedded in Prodorite compound, the whole being supported on a concrete base. I t may

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be used immediately after laying. Among users of this material are manufacturers of chemicals, dyes, artificial silk, margarine, cider and spirits, tanneries, breweries, gal- vanizers, laboratories, sewage undertakings and dairies, a range wide enough to show the many uses to which this type of flooring may he put.-Chew. Age, 19,395 (Oct. 27,1928).

Australia and U. S. Exchange Insect Pest War Information. The stratem used in the United States in warfare against crop-devouring insects will find application in Australia, as the result of the visit of W. B. Gurney, government entomologist of New South Wales, in America, following the Fourth International Congress of Entomology a t Ithaca, N. Y., last summer.

Mr. Gurney has visited experiment stations in a number of the western states, whose agricultural and horticultural problems are more or less similar to those of New South Wales. In Utah he found that the poisons used against the alfalfa caterpillar were like those employed in Australia, hut that the American farmers were finding i t possible to use a much higher concentration than had hitherto been considered safe in Australian practice. Western American attacks on the grasshopper plague also yielded useful information.

The Australian entomologist found citrus growers a t the Riverside Experiment Station in California using Australian parasitic insects in their campaign against the mealybug. It is expected that these parasites will save California orchardists many thousands pf dollars annually if they can be thoroughly established in their new home.- Science Sewice