33 



other end touching the blanket. The arrows show 

 the currents of rising and descending air. But this 

 structure has since been much improved upon, and 

 the following, erected by Mr. Meeks, is the most 

 perfect hitherto promulged. The furnace, bricks, &c. 

 cost less than £ 1 9, and there is no doubt that no ex- 

 pense was spared in this model erection. We are in- 

 debted to the Gardener's Chronicle for the following 

 plans and details. 



Fig. 1 . Plan of house, showing cold air entrances, 

 cold air drains, hot air chamber, and entrances for air 

 into the house, with furnace, chimney, and direction 

 of currents ; a, a, cold air entrances, covered at plea- 

 sure with a horizontal lid outside the house ; b, b, 

 cold air drains, covered at pleasure with sliding covers 

 made of slate ; c, c, entrances for hot air into the 

 house, which may likewise be covered at pleasure with 

 doors sliding along the face of the pit ; d, the fur- 

 nace. 



