i HORTICULTURAL TOUR. 



For increasing and keeping steady the temperature in 

 several of Ins hot-houses, Mr Andrews has of late em- 

 ployed steam y in aid of the ordinary flues conveying smoke 

 and heated air. The steam is carried through the house 

 by means of metal pipes, which are laid along the top of 

 the brick flues. The pipes are of copper, on account of 

 its expanding less than lead. 1'hey are of a square form, 

 ami are set on edge, so that any condensed vapour trick- 

 ling to the bottom may occupy little room, or present only 

 a small surface. As in the common steam-engine, the boil- 

 er is mads to regulate itself by a simple contrivance : it is fur- 

 nished with a float, which descending in proportion as the 

 water is dissipated in steam, in due time raises a valve and 

 admits a new supply of water. The superfluous condensed 

 vapour also returns to the boiler, there being no other provi- 

 sion for disposing of it. It is scarcely necessary to add, that y 

 by merely opening a valve, the house can at pleasure be 

 steamed, i. e. filled with steam, than which nothing can be 

 more conducive to the health and vigour of plants confin- 

 ed in a hot-house *. By this plan there is a considerable 

 saving in the article of coals, which, in districts where 

 this kind of fuel is sea-borne and costly, becomes of import- 

 ance. We were assured, that seven bushels of coal go a* 

 far in keeping up the steam-heat, as ten bushels do in 

 maintaining an equal temperature the other way. When 

 the aid of steam is resorted to, the temperature is found 

 to be more easily regulated, continuing equable for a very 

 considerable length of time. Mr Andrews junior men- 

 tioned, that the furnace being duly charged, and the boiler 

 prepared, he could with confidence leave the hot-house for 



• Mr Pruer, founder in Long Acre-, manufactures th i kettle, pipes, &ev 

 vUurh .ire most approved by the gardeners in the vicinity of London; but 

 wc have brawi-found'.TS in Edinburgh who could easily make the whole., 



