RURAL ENGINEERING. 489 



lending to a peripheral recess on the disk iuto which the skiift milk is conducted. 

 Thence it is withdrawn by means of a scoop-like tube dipping into the recess 

 but fixed on the stationary part of the iippnratus; this tube is providoil with a 

 iionreturn valve." 



Farm ice houses, B. S. Pickktt {Mass. Crop Rpt., 26 {WIS), No. 5, pp. 38-^5, 

 figs. 4). — This article deals with typos of ice storaj^e houses, including ice pits, 

 ice stacks, makeshift ice houses, and modern well-built ice houses. The im- 

 portance of good drainage, ventilation, and insulation is emphasized, dead air, 

 wood, and paper being considered the most effective insulating materials. A 

 modern well-built ice house, holding from 30 to 50 tons of ice, of solid con- 

 struction, properly drained, and neat in appearance is said to cost from .$50 to 

 $125 according as the farmer supplies or hires his own labor and material. 



The silo — how to make it permanent {Brick and Clay Rcc, J/S {191S), No. 8, 

 pp. 7S0-7S8, figs. 17). — This article notes the essential considerations for a first- 

 class silo, analyzes and gives data for the design, and illustrates and describes 

 the construction of reinforced burned clay block silos. 



A combined silo and water tank {Cement Era, 11 {1013), No. 11, pp. SJf, 33, 

 ^g^ J), — The design and construction of this reinforced concrete structure is 

 described and diagrammatically illustrated. The silo proper is of ISG tons 

 capa-city, 14 ft. in diameter, and 48 ft. 6 in. high. The tank on top is 9 ft. 

 high, 14 ft. in diameter, and has a capacity of 10,360 gal. 



The pneumatic water system, J. H. Beattie {Gas Rev., 6 {1913), No. 9, 

 pp. 46, 48, 50, figs. 4). — A simple explanation of the principles involved and of 

 ihe proper methods of connecting up the various types of pneumatic water 

 systems is given to prevent the common difl3culties met with, due largely to 

 the improper application of principles. It is stated that the pneumatic water 

 system when properly inst;illed and or)erated should give as good service as 

 any isolated system, but that proper design and first-class workmanship can not 

 be urged too strongly. 



A mechanically cleaned Berkefeld filter, Grimm {Mitt. K. Landesanst. 

 Wasserhijg. Berlin-Dahleyn. 1913, No. 17, pp. 40-60, figs. 2).— This article de- 

 scribes an improved Berkefeld filter, which is mechanically cleaned by means 

 of the agitating effect of water and air pressure on a cleaning medium of 

 anthracite grit, and is sterilized by using hot steam in place of air and watei 

 pressure. 



The results of 172 tests of this apparatus are reported in which 1-hour filter 

 periods were immediately followed by 10-minute cleaning periods. Both filter- 

 ing and cleaning were done under 3.5 atmospheres pressure. The apparatus 

 was sterilized once a day with steam under atmospheric pressure, this oi>eration 

 taking 30 minutes. Water from the Spree River was used which contained a 

 large number of bacteria and was also very turbid, resulting in a rapid clogging 

 of the filter. 



The results of these tests lead to the conclusion that until the filter cylinders 

 break a practically bacteria-free filtrate may be obtained and that the mechani- 

 cal cleaning of all the filters in 10 minutes is feasible and reestablishes the 

 original filtering effect. 



Design of Imhoff sewage plants, L. C. Fr.\nk and F. Fries {Engin. Rcc, 

 69 {1913), Nos. 17, pp. 452, 453, fig. 1; 18, pp. 501, 502, figs. 3; 19, pp. 519, 521, 

 figs. 2). — In this series of 3 articles is summed up the 7 years' experience of 

 the Emscher River Board in Germany in the design of Imhoff settling tanks. 

 Part 1 reviews some fundamental considerations, and gives suggestions relating 

 to the selection of preliminary screens and proportioning of grit chambers; part 

 2 makes suggestions relating to the length and cro.ss section of the settling 

 compartment, velocity of flow, detention period, and scum boards and baffles; 



