684 EXPERIMENT STATION KECOED. 



explains especially how chemical and bacteriological examinations supplement 

 one another in determining the character and quality of potable water. 



The treatment of waste waters from tin and lead mines, g'ut factories, and 

 piggeries, G. B. Kershaw {Surveyor, 47 (1915), No. 1209, pp. 404, ^05).— This 

 article states that the sewage from piggeries is often ten to fifteen times as 

 strong as domestic sewage of average strength. " The total dry-weather volume 

 of liquid sewage per pig may amount to some 4 to 5 gal. daily, and during rainy 

 days there will be a considerable addition to this quantity. . . . 



" Preliminary treatment of such a strong liquid is best carried out by 

 precipitation with lime in settling tanks, constructed in duplicate, each of them 

 having a capacity equivalent to about IJ days' flow of sewage. The tank 

 liquor is best treated on deep percolating filters of medium-sized material, and 

 the filter effluent should be passed through shallow sand-straining filters. Un- 

 less a very low rate of treatment is adopted — say 20 to 25 gal. per cubic yard 

 per 24 hours — a good effluent can not, as a rule, be uniformly obtained, and in 

 general it is much better, wherever practicable, to dilute the tank liquor with 

 from two to three times its volume of clean water, and then to filter at a rate 

 of about 75 gal. per cubic yard per 24 hours." 



The separation and removal of microbes suspended in water by a stream 

 of air, A. Teillat and M. Fouassieb {Compt. Rend. Acad. Sci. [Paris], 158 

 (1914), No. 7, pp. 518-521; ahs. in CJiem. ZeiitU., 1914, I, No. IS, pp. 1294, 1295; 

 Wasser u. Ahwasser, 8 (1914), No. 8, p. 4S1)- — An experiment is described which 

 showed that with a water of constant surface tension containing different 

 microbes in suspension the admission of a stream of air not only forced the 

 microbes to follow the air but effected their separation according to their size. 



Dynamite experiment, F. G. Spring (Agr. Bill. Fed. Malay States, 2 (1914) f 

 No. 11, pp. 297, 298). — The results of experiments conducted at the Experimental 

 Plantation at Kuala Lumpur on soil of a poor lateritic nature on which the 

 rubber plants were backward in growth are reported. 



Three rows, each containing 34 trees were used, two rows being kept us con- 

 trols. The cartridges were placed at a depth of 2^ ft. below the ground sur- 

 face, one between two trees 12^ ft. apart. After seven months and a few days 

 the average increase in girth was 2.56 in. in the dynamited row, and 1.81 and 1.62 

 in. in the control rows. 



On the use of explosives and of the blow lamp in the garden, H. E. Durham 

 (Jour. Roy. Hart. Sac., 40 (1914), No. 1, pp. 7-18). — This report is in two parts. 



The first, dealing with the use of explosives, briefly describes methods of 

 procedure in blasting soils and reports experiments made to determine the value 

 of explosives for loosening the soil on small areas, such as intensely cultivated 

 gardens. 



Cheddite cartridges with 2, IJ, 1, and i oz. charges were placed 3 ft. apart 

 and at a depth of 3 ft. Potatoes responded in a marked manner to the use of 

 the explosive, the i-oz. charges being accompanied by about 15 per cent increase, 

 the 1-oz. by 43 per cent, and the 2-oz. by 88 per cent. Cauliflower and cabbages 

 showed no appreciable difference in blasted and unblasted soils. With peas the 

 number of plants was much smaller on the unblasted side but they blossomed 

 and matured a week earlier than on the blasted soil. Carrots, onions, and 

 Scorzonera gave a greater number of plants and germinated and developed 

 much better on the blasted soil. This was particularly marked in the case of 

 Scorzonera. 



In the second part the use of the plumber's blow lamp for the destruction of 

 weeds and insects is briefly described. 



Blast furnace slag in concrete, W. A. Aiken (Iron Trade Rev., 55 (1914), 

 No. 1, pp. SI, 32; abs. in Indus. Engin. and Engin. Digest, 14 (1914), No. 9, 



