Opening windows in greenhouses and hothouses

2156. In greenhouses and other houses where the heat maintained is not much greater than that of the atmospheric air during the middle of a fine day, all that is required is to supply some means of opening the windows simultaneously, so as to afford a supply of air to every part of the house at the same time; and various modes have been devised for doing this with the least possible trouble to the gardener, some of which have been already described; but the best of which is probably that in constant use in the Royal Gardens at Frogmore. [Windsor]