ON HEATING PLANT STRUCTURES. 275 



which bark or sawdust, &c., is put, in order to plunge pots of cuttings 

 therein. The chamber is continued at the opposite side of the liouse. 

 A pathway three feet wide extends up the house ; on its right, in 

 entering, is the heated chamber we iiave described, and on tiie left a 

 second one, the bottom of which is level with the floor of the house ; 

 this is two and a half feet wide ; and beyond it is a third chamber, of 

 which the bacic wall of tlie house forms one side, and another one, at 

 two and a half feet from it, inside the house, forms the width of tliis 

 third chamber. Its bottom is about nine inches above the surface of 

 the chamber number two. The heated air filling these chambers, they 

 are heated to any desired temperature, as high as °, if required. 

 In order to admit the warmed air into the house, ventilators are affixed 

 in the inner sides of the chambers, and as they are the turn ventilators 

 they are readily opened or shut. By this means a regulation of tempe- 

 rature is furnished in the most satisfactory manner. In order to have 

 a moist atmosphere, a pipe enters into the fire-box, and several perfo- 

 rated pipes extend over the heated ones ; water being poured into tlie 

 pipe, is distributed over them, and a steam is readily produced for the 

 house.* 



We never saw cuttings of plants take root so early and freely as 

 they do in this house ; and the plants which are generally kept in the 

 house grow vigorous and healthy. 



The temperature of the house during the severe frost of the winter 

 was 72° at eight o'clock in the evening, and 70° in the morning at the 

 same hour. Tlie diflTerence of temperature in the honse is 1° higiier 

 at the end where the fire-box is than at the opposite end where the 

 door is. The cost of coke per twenty-four hours, in the winter, is from 

 three-pence to four-pence, and that estimate formed upon the high 

 price given for it at Richmond, viz., sixpence per bushel. The cost of 

 fuel in the hot-water system with us is four times that of Hazard's. It 

 requires no attention from six or seven o'clock in the evening to eight 

 or nine tiie following morning. 



Hazard's system obviates what is strongly protested against by 

 many persons ; it does not admit the air in the house to pass suc- 

 cessively and continuously over the fire into the house, but it admits a 

 continuation of fresh air to any definite period, if the mouth of the air- 

 drain be kept open as well as the ventilators in tlie liouse, thus pro- 

 viding a suitable atmosphere for the plants to flourish in, and at a cost 

 lower than by any other system we have seen or heard of. The escape 

 of tiie air out of the house is only by the laps between the panes of 

 glass, and it is found quite suflicient ; it gradually and gently passes 

 through, so as to keep the temperature at a suflScient height, and that 

 in a state of equality for a long period. 



The entire apparatus is simple and economical, maintains a regular 

 temperature with little attention, and scarcely can be deranged even 

 by tlie careless. It can be made equally available to the smallest 



* We tbink a tank, in -which a due portion of -water is poured, being fixed upon 

 the surface of tlie fire-box, -would be better than the pipes which distribute thg 

 ■water. We shall try it in another house,— Conductor. 



