430 ENGINEERING ON THE FARM 



The Underwriters Laboratory, 382 Ohio Street, Chicago, 

 Illinois, will furnish a list of manufacturers of approved 

 acetylene or air-gas plants. 



ELECTRIC LIGHT 



Probably the most attractive method of illumination is by 

 electricity. The introduction of modern high-efficiency 

 lamps has been a great incentive to the development of small 

 isolated electric-light plants. 



Public utility service. The first question arising when a 

 lighting system is desired is whether electrical service may be 

 had from a neighboring town or village. If this may be 

 had, there is little occasion for giving much thought to the 

 isolated plant. The general service from a city or village will 

 furnish electricity at a price which will allow its use through 

 motors, with such efficiency that gas engines maybe dispensed 

 with on the farm. If the public service corporation cannot 

 be induced to furnish current, it will then be necessary to 

 consider the isolated plant, but it will not be practical to 

 install a number of small motors which may be supplied from 

 your own generator and storage-battery system. This latter 

 statement is made because of the low efficiency of the low- 

 voltage motors, there being too large a loss in transferring 

 the energy from the generator to the storage battery and 

 back through a motor in the low- voltage system. 



Volt. To make this clear, let it be understood that a volt is 

 the pressure which forces electricity along a conductor. It 

 is analogous to the pounds pressure on a water pipe. The 

 ampere is the quantity of flow through the conductor due 

 to the voltage, resistance being an element. The ampere 

 is analogous to the water which will flow from the end of 

 the pipe because of the pressure, providing the pipe is not 

 so long that the resistance overcomes the pressure. The 

 conductor in each case may be so long that there is no flow. 



Watt. A watt is a quantity which involves both the volt- 

 age and the amperage. The two multiplied together will 



