88 EXPERIMENT STATION EECORD. [Vol.38 



transmission was increased 0^ B. t u. by increasing the humidity from 74 

 to 84 per cent, which is equivalent to a change of 24 per cent in transmission 

 for a variation of 10 per cent in relative humidity. For red brick the unit 

 transmission was increased 0.102 B. t u. by increasing the relative humidity 

 from 80 to 90 per cent, which is equivalent to a change of 15 per cent for a 

 variation of 10 per cent in relative humidity. 



" The effect of velocity on the transmission of heat . . . varies greatly, de- 

 pending upon the arrangement for conducting the air over the surface tested. 

 In the case of glass the unit transmission corrected to 80 per cent humidity, 

 and at 1,000 ft. per minute velocity has these values: Two and nineteen- 

 hundredths B. t. u. for a cube equipped with spouts ; 4 B. t. u. for cube equipped 

 with air cone alone. These facts show very conclusively that in studying the 

 effect of velocity upon the transmission of heat through a material the arrange- 

 ment of apparatus for protecting that portion of the material which is considered 

 under still air conditions is of the utmost importance. . . . 



" In the test made upon diatomite briclc . . . the number of tests were small 

 [and] no definite conclusions can be dravra, but from the results obtained the 

 unit transmission does not remain constant, but varies directly with the tem- 

 perature within the test box." 



Tractor hitches and adjustments for use with power plows, C. H. Gamble 

 (Farm Machinery, No. 1342 (1917), pp. 9, 10, figs. 5). — Hitches and adjustments 

 are described and illustrated. 



Harvesting hay with the sweep raise, A. P. Yeekes and H. B. McClube 

 (Z7. S. Dept. Agr., Farmers' Bui. 838 (1917), pp. 12, figs. 11).— The purpose of 

 this publication is to suggest to hay growers in the Eastern States the possi- 

 bility of using the sweep rake as a means of saving time and labor. " The 

 sweep rake consists of several long wooden teeth lying almost flat on the ground, 

 pointed at one end and fastened to a strong framework at the other. The point 

 frequently consists of a steel cap fitted over the end of the tooth and shaped 

 so as to prevent it from running into the ground under ordinary conditions, 

 yet so as to slip under the hay, no matter whether lying in piles, windrows, or 

 swaths. The teeth usually are about 8 ft. long and placed approximately 1 ft. 

 apart. The total width of the rake ordinarily is about 12 ft., rakes of this 

 width having 13 teeth." Different types of sweep rake, including the wheelless, 

 two, three, and four wheeled styles are described and illustrated. 



" The use of a sweep rake in hauling hay from windrow to stack or barn 

 under most eastern conditions can reasonably be expected to effect a reduction 

 of 50 per cent in the cost of doing this work by the method now commonly used, 

 L e., pitching onto a wagon by hand and hauling to stack or barn. 



" Extensive investigations of the efiiciency of various methods of handling 

 hay, made by the Oflace of Farm Management, show that by the latter method 

 two men pitching onto a wagon and one man loading usually will haul from 

 6.5 to 8 tons of hay in one afternoon of six to seven hours. This will Include 

 putting the hay into the mow with the same crew, using hay fork or sling. A 

 two-man crew in the same length of time, using two sweep rakes and four 

 horses, with the average length of haul in the East, which is less than 0.25 mile, 

 will haul to the barn and put into the mow with slings about double the amount 

 of hay handled by the three-man crew working with a wagon. If the hay is 

 stacked in the field, three times the amount will be handled, although the third 

 man will be required on the stack." 



Management of common storage houses for apples in the Pacific North- 

 west, H. J. Ramsey and S. J. Dennis (V. S. Dept. Agr., Farmers' Bui. 852 

 (.1917), pp. 2S, figs. 6). — This publication deals with the fundamentals of con- 



