ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



11 



when the requisite'temperature has heen attained, d is theu pushed in to 

 arrest the flow. As the temperature falls, the volume of air in g and I 



Fig. 7. 



Fig. 8. 



<LA 



SS22I 





will diminish, and the piston h will travel in the direction of a, and so 

 open d by removing the plate p. Fresh hot water then flows through, 

 and the temperature rises, and so on. In this way any temperature 

 Feb. 21st, 1900 I 



