114 VENTILATION OF EAELY FORCING HOUSES. 



either with or without being moistened before it reaches the 

 plants inside the houses ; or the moisture may be directly ad- 

 mitted from the tanks by other means, in the exact quantity 

 required at any particular stage of growth. The advantage 

 gained by this plan is a greater command over the moisture of 

 the atmosphere ; though in a forcing-house such a power would 

 seldom be required to be put into practice. 



Another mode combining internal motion with ventilation, 

 and by which the cold air is warmed before it reaches the plants, 

 has been practised with very marked success during the season 

 of 1845, in a vinery at Park Hill, Streatham, under the direction 

 of Mr. Dodemeade, gardener to William Leaf, Esq., F.H.S. 

 This plan consists in passing a zinc pipe, thickly perforated vfhh 

 small holes, from end to end of the vinery, and exactly beneath 

 the range of hot-water pipes which heat the structure. In the 

 outer wall, communicating with this perforated pipe by means of 

 a kind of broad funnel, a register valve is fixed by which the 

 admission of air can be regulated with tlie utmost nicety, or the 

 supply be shut oflT altogether : tliis valve is fixed a little below the 

 level of the perforated pipe. The action of this contrivance was 

 evident enough from the motion communicated to the foliage of 

 the vines ; and its effects were apparent in the unusually healthy 

 and vigorous appearance they bore, until their period of ripening. 

 In this case, suflficient moisture was kept up by syringing the 

 walls and pipes, wetting the pathway, and by the use of evaporat- 

 ing troughs placed on the metal pipes, and kept constantly filled 

 with water. 



XIII. — A Note upon the Wild State of Maize, or Indian Com. 

 By the Vice-Secretary. 



When Maize was first noticed by writers on Rural afl^airs it 

 had already acquired the name of Turkic Corn, Corn of Asia, 

 Spanish Corn ; and hence it was thought to have had an Asiatic 

 origin. Parkinson, who wrote in 1640, even fancied that it 

 might be the Bactrian corn mentioned by Pliny.* But Gerarde 

 gave a more correct history of its introduction : — " These kinds 

 of Grain," he says, " were first brought into Spain, and then into 

 other provinces of Europe ; not (as some suppose) out of Asia 

 Minor, which is the Turk's dominions, but out of America and 

 the Islands adjoining, as out of Florida and Virginia, or Norera- 



* " Tradunt in Bactris grana tantae magnitudinis fieri ut singula spicas 

 nostras sequat."— (/fts<. Nat., lib. xviii., c. 7). 



