March, 1936] Agricultural Research in N. H. 23 



roof cement and covered by matched flooring ; two layers of the same type 

 of insulating board and water-proof jacket ; and three layers of the insulat- 

 ing board sealed in tar paper were used. 



The floor temperature curves showed the same general characteristics 

 as during the 1933-34 runs — that is. a marked drop shortly after midnight 

 with a slow, irregular rise often late the following afternoon. Thermocouple 

 readings taken intermittently showed very little indication of any major 

 heat loss through the floors, as a matter of fact, when continuous all night 

 readings were taken, the temperature under the floors never changed as rap- 

 idly as the temperature within the houses, (because they were well banked 

 and boarded up below) . 



From the temperature readings the loss through the floor appears so 

 small that the "built-in" insulation was not warranted. There was absolutely 

 no correlation between floor insulation and mortality. 



From the cost and labor records which were kept on all operations, it 

 was found that the cost for brooding with electricity is practically the same 

 as with coal. Taking averages of all runs with electricity, the current plus 

 labor was about 6.4 cents per bird for 6 weeks, while coal plus labor ran 

 about 6.3 cents for the same period. (Electricity figured at 3^ per kw. hr., 

 coal, $14 per ton.) 



The lowest electricity plus labor cost on any run was 5.5 cents, while the 

 highest in a 10' x 12' house was 7.1 cents per bird. (W. T. Ackcnnaii, G. M. 

 Foulkrod, T. B. Charles, A. E. Tcppcr and P. D. Reed—PnrncU Fund.) 



Pneumatic Tractor Equipment 



In general, pneumatic tire equipment for tractors has proved to be very 

 practical and successful in the Station tests. After two seasons of use the 

 feather-edge mould mark is still in evidence. Some gouging and chipping 

 of the treads has occurred, and two tears of the rubber casing down to the 

 first layer of cords has occurred. This latter difficulty was experienced with 

 both sets of tires and is in the nature of accidental injury. 



In operation it has been found that even under the severest conditions 

 of moisture that pneumatic tires, unlike steel wheel equipment, will not dig 

 themselves in. A shallow trough is dug in the soil and the wheel will slip 

 continuously in this trough without increasing the penetration. All of the 

 results above indicated a not too efi^ective tread design. 



A difl^erence in traction was found between the two rear wheels on 

 account of one being in the furrow and the other on unplowed or grass land. 

 In order to decrease the slippage which resulted, four weights, weighing 

 from 160 to 165 pounds, were used on the rear wheels in various combina- 

 tions. 



It was also found that under moist and very wet conditions, slippage 

 was excessive, and some traction accessory would be necessary to make 

 equipment usable under such conditions. Special lug-type mud chains, de- 

 veloped by a commercial concern, were purchased to overcome this difficulty. 

 In use these were found to be so heavy that the operators were not likely 

 to apply and remove them at times when they should. Also, the spacing of 

 the lugs was so great that in operation upon firm ground a very bumpy 

 motion was developed. This was sufficiently uncomfortable to the driver to 



