368 APPLIED SCIENCE 



and this product by the number of revolutions per minute and 

 dividing the final product by 15,000. What is the horse-power of a 

 four-cycle gas engine with a 5 in. bore, 6 in. stroke, and 400 R. P. M.? 



2. The proportion of gas and air in an explosive mixture is or- 

 dinarily a mixture of one volume of gas to seven to ten of air. How 

 much air should be mixed with 6 cu. in. of gas? 



3. The maximum pressure in a gas-engine cylinder may be cal- 

 culated approximately by multiplying the gauge pressure of corn- 

 pressure by four. What is the maximum pressure in a gas-engine 

 cylinder if the gauge pressure is 70 Ibs.? 



