ADVAXTAGES OF STEAM. 21 



doubled accordingly. The cisterns are farther semceable in regulating 

 the humidity of the house, which can be done with the greatest accuracy 

 by attending to the covers." 



Several other modes of heating by steam could be mentioned, but as 

 they appear to us to possess no particular merit over those already noticed, 

 we think it supei^uous to allude to them. The most complete and 

 scientific steam apparatus hitherto erected in this country for heating 

 plant houses, is that of his Grace the Duke of Northumberland, at Sion 

 House ; this was erected entirely imder the superintendence of the late 

 ^Ir, Tredgold, a civil engineer of great professional attainments, who was 

 cut off in the prime of life, a loss to all who had the pleasiu-e of his 

 acquaintance, as well as to science. 



