THE PEOPLE'S PRACTICAL POULTRY BOOK. 163 



the lever, O, may have free play when the valve is closed or opened to its 

 utmost extent. A similar result is obtained by the use of the spring, V, 

 which permits the lever to rise after the regulator has closed over the tube 

 to its utmost extent. 



THE REGULATOR AND TUBE 



are so arranged, however, that the flame cannot be entirely extinguished by 

 the operation described, while the flame is graduated from a full blaze to a 

 very faint one. 



THE GREAT DIFFICULTY IN ARTIFICIAL HATCHING. 



It is well known that the great difficulty in artificial hatching is that of 

 maintaining a regular temperature, particularly in so variable a climate as in 

 the Northern States. The difference of temperature between day and night 

 has to be carefully provided for, and constant reference must be had to the 

 thermometers. This difficulty has heretofore been a great obstacle in the 

 way of the artificial hatching of chickens. By this invention, is obtained a 

 constant and even temperature at all times, provided, of course, that the 

 lamps are capable of producing sufficient heat for all exigencies. 



THE PERIOD OF INCUBATION BY THESE MACHINES. 



M. VALLEE, an inventor of one of these machines, in giving the result of 

 his experience touching the period of incubation necessary for the various 

 species of eggs, states what is curious and worthy of record. For chickens it 

 takes twenty-one days; partridges, twenty-four; pheasants, twenty-five; 

 Guinea hens, twenty-five; common ducks, twenty-eight; pea fowls, twenty- 

 eight; Barbary ducks, thirty; geese, thirty; turkeys, twenty-eight. The 

 degrees of heat required to effect the above result are from one hundred and 

 four to one hundred and ten degrees Fahrenheit. 



ARTIFICIAL HATCHING OF DUCKS IN CHINA. 



In closing our remarks on the use of incubators and artificial mothers, we 

 have deemed it not improper to give, from Commodore PERRY'S report of his 

 voyage to Japan, the mode used by the Chinese in hatching ducks' eggs by 

 artificial means. After visiting the hatching chambers he carefully details 

 the plan of the Chinese, as follows : " There was 



NO ARTIFICIAL HEAT IN ACTUAL USE 



while I was there. The temperature of the external atmosphere was at 

 about ninety degrees Fahrenheit, and there was a small chamber with a 

 number of furnaces and charcoal, ready to be lighted and put into requisition 

 at very short notice. The front room had large shelves on the two sides, 

 about four feet deep from the wall, extending the whole length, the lower 

 about a yard from the ground, and two others about eighteen inches apart. 

 These shelves were appropriated to eggs which were within two or three 

 days of their term. The shelves were first covered with two or three thick- 

 nesses of heavy, spongy paper, almost as thick as a blanket, which appeared 



