22 N. H. Agr. Experiment Station [Bulletin 289 



The complete survey record includes, among other things, a description 

 of the electrical situation in each district, summaries of the Group "A" and 

 Group "B" extensions, with estimated costs and revenues and town maps 

 showing the existing electrical facilities of all types within the town, all 

 possible customers in the unserved areas down to a density of one per mile, 

 etc. 



The availability of such detailed information makes it possible for all 

 state agencies interested in developing this field to work with the minimum 

 loss of motion and expense toward as completely an electrified agriculture 

 in the state as can reasonably be accomplished. (W. T. Ackcnnan — State 

 Fund.) 



Precooling of Milk 



Experiments on the precooling of milk using the wet tank storage type 

 were continued with refrigeration equipment involving circulating gas and 

 a minimum of mechanically operated valves. 



Being of a unit type, it was possible for the first time in the experience 

 of this Station to measure the output capacity of the equipment directly in 

 pounds of ice formation. This is a standard unit of capacity used through- 

 out the refrigeration industry, but up to this time has been arrived at in the 

 field of agricultural refrigerating equipment by computation. A method was 

 evolved whereby the ice formed was measured in pounds directly. 



The year's study also included investigation of the efficiency of bottom- 

 type evaporator or cooling units, and also a new cast-iron radiator type with 

 fins, located in a vertical position in the center of the bath. For the space 

 occupied by the latter kind it was found that satisfactory cooling could be 

 obtained with a reduction in the over-all size of the tank. While the cooling 

 effect produced by bottom-type evaporator units is satisfactory, it is found 

 necessary to increase the height of tanks to accommodate them, thereby mak- 

 ing it more difficult to lift the cans in and out. 



One of the difficulties experienced by users of wet tank milk cooling 

 units up to this time had been the length of time required to complete the 

 cooling of the milk. This has been largely due to inadequate circulation in 

 the water bath — many tanks having no provision for this other than the very 

 slow circulation produced by convection currents. The most significant find- 

 ing of the year was that a ^" iron rod mounted vertically in a tank and 

 having a straight line sweep motion at its bottom point, of about 18", when 

 operated by the compressor unit motor, at a rate of about 100 complete 

 strokes per minute, will produce a uniform temperature throughout the entire 

 mass of the water bath. From this it would seem that the use of circulating 

 pumps (usually driven by a separate motor) requiring a considerable in- 

 vestment and amount of power to operate and which put the water in motion 

 with considerable velocity may be supplanted by this less expensive equip- 

 ment which will produce practically perfect temperature distribution. (W. 

 T. Ackerman, H. C. Moore — Purnell Fund.) 



Heat Requirements for Brooding Chicks 



Various types of insulation for brooder-house floors were studied in a 

 continuation of the work with electric brooders. (See Station Circular 46.) 

 A double wood floor ; a layer of ^" insulating board, sealed in tar paper and 



