REMARKABLE INCREASES ARE SHOWN 



575 



The beneficial influence of the lengthened day is beyond dis- 

 pute. If it does not increase the total annual production very 

 much, at least it gets the hens to lay more eggs in winter, when 

 eggs are worth considerably more, thereby adding greatly to the 

 profits of the poultryman. 



On a farm in western New York accurate records were kept for 

 a two-year period, and not only was the total egg production in- 

 creased l8 per -cent by artificial light, but the winter part of the 

 production, from December to March, was increased 70 per cent. 



^ 4^ 



{Courtesy Washington Experiment Station) 



Fig. 342. — Fixtures for artificial lighting. Left-hand diagram shows tube 

 system of gasoline mantle lights. ' By the operation of a needle valve in the 

 generator any degree of illumination may be pi-oduced throughout all the 

 lights at the same time. Right-hand diagram shows portable gasoline mantle 

 lantern, suitable for small house. 



Lights were used morning and evening, from the middle of 

 November to the first of April. - ' 



Other Essential Factors. — ^Though artificial lighting is the im- 

 portant factor in obtaining and keeping a uniform schedule of egg 



