AGRICULTURAL MACHINERY AND IMPLEMENTS IO53 



the net cost of the work) varies in the proportion of i to 3, according to 

 type of soil and the depth of ploughing. On these data M. de Poncins, 

 agricultural advisor to the « Union du v*>ud-Est >• (France), instead of taking 

 as a basis the area and depth of work or the time taken, has found it mftch 

 simpler to base his costs on the acUial consumption of petrol on the work. 

 The members thus pa}' only for petrol used, at net price, plus a sur- 

 charge of IS lod per gallon to cover other costs, calculated in the follow- 

 ing way: 



Assuming that the tractor works on a average 150 days each year, at a rate of 5 acres per 

 day, or 750 acres per annum, and that, on average soils it uses about 4 ^/^ gallons of petrol per 

 acre. The surcharge then amounts to 8s id per acre, divided as follows : 



s d 



Depreciation of tractor: £.480 in 4 years. . . 3 i Y2 



Labour : 2 men i 7 



Oil, grease, waste 11 V2 



Insurance : fire and accident : £13 per annum. . 4 



Repairs : £36 per annum 11 V2 



Spares, general expenses, sundries i^ V2 



Total per acre . . ■. 8 i 



These annual costs amount to £300 for 730 acres, or 6::. 5 per cent of the price of the 

 tractor. 



For example, if a member's job has. consumed 88 gallons of petrol, 

 he pa^-s the society the cost of 88 galls, plus 88 X is lod -- £ S is ^d. 



Taking the net cost of petrol at 2s gd per gallon and supposing two 

 ploughing jobs, one in light soil using 2.1 gallons per acre, the other in very 

 hea\'y soil (5.3 gallons per acre), in each ease the cost per acre will work 

 out as follows: 



Soil 



Petrol used. 

 Surcharge . 



Total ... 12 I 1/2 £143 



Accounts are thus easy to make out and the management is simpler, 

 since it is only necessary to measure the petrol used. 



1 208 - Dust Explosions and Fires in Grain Separators in the Pacific Northwest. — 



Price J., in United Stales Department of Ag,ricullitre, Bulletin, No. 379. Washington, 

 D. C, August 1916. 



In a very detailed study, the writer examines in the first ])lace the caus- 

 es which have produced some 166 ex]:>losions from the middle of July to 

 che end of September 1915. He then shows the means used for fighting 

 these as well as the results obtained which were most conclusive. 



A whole series of observations have made under the direction of the 



