BOYLE'S INCUBATOR. 



71 



constructed elaborate incubators. The principal object with all 

 inventors was to ensure an equable temperature, but few of the 

 ingenious contrivances employed really secured this, and 

 adequate attention was not, as is now known, paid to the 

 proper amount of dampness, or to purity of the atmosphere. 

 All the machines at times hatched remarkably well, but not 

 one could be depended on to hatch well; and the first incubator 



H 



A 



Fig. 14. Boyle's Regulator. 



which really did uniform good work in intelligent hands 

 was that invented by Mr. Henry Boyle. This greater uni- 

 formity was due to the delicacy of its (patent) heat regulator, 

 shown in Fig. 14. 



A c is a* glass syphon-gauge, connected at B with the heating 

 water, heated air, or other medium it is desired to regulate. 

 The water, A, extends to nearly the bottom of the longer leg of 

 the syphon, pressing near the bottom upon the mercury, c. 

 This is connected by a short piece of vulcanised india-rubber 

 tube, D, with the nearly horizontal small glass tube, E, which 



