108 POULTRY BREEDING IN 



uniform temperature are impossible to maintain, con- 

 sidering the variations in the temperature of the atmos- 

 phere, I consider artificial hatching too expensive for 

 ordinary purposes, and only to be adopted at certain 

 times of the year, and then only in establishments where 

 the heat can be maintained at a uniform temperature, 

 day and night, by personal care. 



At the Jardin des Plantes, in Paris, the manager of 

 the poultry department, M. Vallee, employs an ap- 

 paratus of his own invention, which he has patented, 

 and for which he has obtained prizes at two exhibitions. 

 The principle consists of water heated by means of a 

 lamp as a medium for hatching : the temperature is 

 regulated by admitting more or less cold air by means 

 of a valve opened or closed by a mercury float. 



At the Jardin d'Acclimatation two systems of artificial 

 incubation are in use, and although both are on the hot- 

 water principle, yet they differ materially : the one is 

 heated by means of a lamp, and the temperature regulated 

 by a valve admitting more or less cold air, and which 

 is effected by a piston acted upon by the expansion or 

 condensation of air under different temperatures ; the 

 other consists merely of a zinc box covered with non- 

 conducting materials. This apparatus requires neither 

 lamp, regulator, or thermometer; the hot water is re- 

 newed every twelve hours ; and it is said to answer 

 admirably. The eggs are placed in a drawer under- 

 neath the water tank, but I cannot help thinking that 

 with an atmospheric temperature at or below freezing, 

 point it would be very difficult to prevent the rapid 

 cooling of the water. 



