THE HYDRO INCUBATOR. 



73 



as chipped, are hatched out in the receptacle or hatching-box, 

 R, on top of the heating-cistern, which is supplied with damp 

 sawdust and cotton-wool to keep up the necessary moisture. 



With people who understood it, this incubator hatched 

 remarkably well ; but it was complicated and costly, and, 

 moreover, the egg-plate sliding under the arches in the heating 

 tank was often found to break eggs at an alarming rate. The 

 bottom of the eggs being kept cool, the top temperature found 

 most successful was about 106. 



Fig. 15. Egg-tray in Boyle's Incubator. 



In 1877 the practice of artificial hatching was revolutionised 

 by what was termed a " Hydro-Incubator," exhibited by Mr. 

 T. Christy, at a Dairy Show held at the Agricultural Hall, 

 London. This machine was modelled upon one used for some 

 little time previously with success in France, made by Messrs. 

 Roullier and Arnoult, and it consisted in the main of a large 

 hot-water tank over the egg-drawer, of peculiar construction, 

 from which a few gallons of water were drawn off twice in 

 every twenty-four hours, to be replaced by boiling water ; thus 

 keeping up the temperature. The attendant was not, however, 

 able to explain the construction of the tank, or the reason for 

 the mode of working ; and the consequence was that not one 

 single individual acquainted with the subject we were 



