INCUBATOR HOUSES AND CELLARS 327 



judgment, skill, and close attention of the operator. The next 

 development of the artificial method was in France during the 

 fifteenth century, but little actual progress was made. In the 

 latter part of the eighteenth century water was first used as a 

 means of supplying heat to the eggs, all preceding work having 

 been done by heated air. 



In 184.5 a self-regulating valve was invented, which regulated 

 the temperature or reduced it when too high. This device opened 

 the way and made possible the modern self-regulating inculDaLor. 

 The following year, in an attempt to imitate the natural method, 

 a special apparatus was constructed to supply heat from above. 

 There was no noticeable advance from this time until the last 

 quarter of the nineteenth century when, owing to the inc^reasing 

 demand for poultry, largely because of increased population, much 

 construction work was done in this country and abroad, resulting 

 in many new and superior types of incubators. 



To Charles Cyphers belongs much of the credit for developing 

 in America the commercial artificial incubator. While he was not 

 by any means the first experimenter in this line, yet he accom- 

 plished much, and made improvements which soon reduced the 

 process to a practical science, and enabled any one of limited 

 means to own and successfully to operate an incubator. Since 

 1870 many improvements have been worked out, with the result 

 that different models have been put on the market. Many of 

 these are good structures of desirable type, but many, too, are 

 faulty in design and poorly built, therefore cannot be expected 

 to work successfully. The aim has been to construct an incubator 

 which would be operated by any one, in any place, with the least 

 possible care and oversight, and in great measure this has been 

 accomplished. Yet in many important ways the incubator must 

 bo improved in order to make it as efficient as the hen. 



Incubator Houses and Cellars. — The successful operation of 

 any incubator depends largely upon the place in which it is located, 

 and the rapidity and ease with which the operator can secure and 

 hold the desired temperature. Therefore, the design, construction, 

 and location of the building or room in which the incubators are 

 to be placed must be carefully considered. The requirements of 

 the incubator room are briefly stated as follows: (1) Even tem- 

 perature, (2) plenty of ventilation, (3) abundance of moisture. 



It must be possible to maintain in the incubator room approxi- 

 mately an even temperaturo, of any desired degree. Variation 



