EXPLANATION OF THE PLATE 



Fi*. 1, is a vertical section of the sand-bath, on a scale of-'-. 

 Fio-. 2, a horizontal section ; the letters of reference are the same in 

 both : A is Mr. Uoberton's door, a species of tube which is con- 

 stantly kept full of coals ; at the upper part of it is seen the slit 

 through which air is admitted. 



B is the fire-place ; the flame proceeds through the flue C into 

 the cavity D, which corresponds to the shape of the sand-pot, leav- 

 ing round it a vacancy of three inches ; here it is constrained to de- 

 scend and surround the bottom of the pot by the stops E E, of 

 baked clay, which are fitted to the sides of the pot. 



The second flue C, conducts it to a second cavity D, arranged 

 as the first ; and it finally escapes through F into a vertical tube 

 fourteen feet high. 



The draught and heat are accurately governed by a semi-circular 

 register in the door of the ash pit, and a sliding door in the chimney, 

 which do not require a particular description. 



