RURAL ENGINEERING. 889 



houses it is iinporlnnt to i:ikt' ;i(lv;uit,i;r(> of tlu> insuhitin.t,' quiilitios of earth 

 and dead air. 



Apertures for ventilation and the intake of cool air are considered neces- 

 sary for air-cooled storage houses, but windows and doors should be reduced 

 to the smallest possible number and size consistent with convenience. It is 

 stated that the exposed side of the house should face the north, where it avoids 

 the direct sun in the daytime and draws in the coldest air at night. 



Ilyirro-tliermograiihic records taken in a storage house of approved construc- 

 tion showed that in comparison with an, outside variation of 37° in tempei'ature 

 the storage chamber showed a total variation of only 11°. Similar records 

 taken in another house showed the same uniformity in temperature, which is 

 considered essential to the success of the storage. 



As- regards the management of an air-cooled apple storage house, it is stated 

 that in preparation for the crop advantage should be taken of every cool night 

 to lower the temperature of the storage chamber as much as possible. The 

 ventilators should be opened after sundown and the whole house closed tightly 

 before sunup, so as to keep out the warm air. The fruit should be allowed 

 first to cool overnight and then 1)0 placed in the storage before sunup. As the 

 weather becomes cooler advantage should l)e taken of it to lower the temi>era- 

 ture and cool down the fruit as much as possible. When all the fruit is in, 

 the house should be opened as little as possible and the fruit left wholly undis- 

 turbed. 



It is stated that the general consensus of opinion among practical cold- 

 storage men indicates that apples should be stored at a temperature of 30 to 

 40° F. and pears 33 to 36°. 



[Construction of creameries and cheese factories], E. H. Faerington and 

 G. ir. Benkendorf (Wisconsin 8ta. Bui. 2U {1915), pp. 20-52. figs. i6).— This 

 deals with the location and general features in the construction and arrange- 

 ment of creameries and cheese factories and illustrates and discusses six differ- 

 ent creamery plans which are considered to exemplify good practice. An inspec- 

 tion score card is included. 



The disposal of creamery sewag'e, E. H. Farrington and G. J. Davis, Jr. 

 {^yis<■onsin Sla. Bui. 2.'t5 {1915), pp. 20, figs. 9\. — It is the purpose of this 

 bulletin to describe and illustrate suitable arrangements for the purification and 

 disposal of creamery .sewage. 



It is stated that creamery sewage is not so quickly purified as city sewage 

 owing to the fact that the curd, oil, and sour milk decompose slowly and the 

 lactic acid from sour milk has a tendency to suppi'ess the growth of purifying 

 bacteria and thus retard the liquefaction and gasification of the solid matter. 

 For this reason where a sedimentation tank is used the waste acid from testing 

 milk and cream should not be allowed to run into the drain. Clean water used 

 for cooling puii:>oses should also be excluded. 



The septic tank, it is stated, should be large enough to hold at least three 

 days' sewage. "The flow maybe estimated (1) by assuming that the amount 

 of sewage from a creamery will be from 1 to 1* gal. for every pound of butter 

 made, or (2) by calculating the amount of water pumped per day or by meas- 

 uring the capacity of the supply tank and deducting from the total water 

 pumix^d the amount used for cooling purposes and not allowed to run into the 

 floor drain." 



Some of the special features to be ob.served in the construction of a septic 

 tank suitable for the digestion of creamery sewage are given as follows: "The 

 cover should be provided with a manhole so that occasionally the sludge at the 

 bottom of the tank may be removed. A grease trap may be placed in the drain 

 between the factory and the tank for the purpose of collecting machine oil and 



