330 On heating Hot-homes hy Steavi^ 



Art. V. A Method of destroying the Red Spide}- iji Hot- 

 houses, Sj'c. By Mr. William Redding, Gardener to Mrs. 

 Marryat, Wimbledon House, Surrey. 



Sir, 

 Allow me to lay before my brother gardeners my method 

 of destroying the red spider in vineries, hot-houses, and peach- 

 houses ; a method I have practised for these ten years with 

 the greatest success. I take half a pound of flower of sul- 

 phur, kill it with a little milk, add half a peck of hot lime and 

 two small balls of whiting, and mix it well with water, until it 

 attains the thickness of whitewash, when it is fit for uje, I 

 then with a brush wash the flues and every part of the nouse, 

 which is of brick, with this mixture. My general practice is 

 to wash the houses with this mixture in the month of February 

 or March ; but, should they require a second washing, which, 

 is seldom the case, they may be done at any time when the 

 fires are on, with the greatest safety, only using it sparingly 

 for 5 or 6 ft. from the furnaces. I am. Sir, &c. 



W. Redding. 

 Wimbledon, August 19. 1828. 



Art. VI. Ow heating Hot-houses hy Steam, through the Me- 

 dium qf Stone. By the Rev. James Armitage Rhodes. 



Sir, 

 I WILL now endeavour to fulfil the promise I made you of 

 describing the mode in which my hot-houses are heated, and 

 I beg to be understood to say no more than that it is a good 

 plan. I do not compare it with the new mode of heating by 

 hot water, because 1 have only lately seen that plan carried 

 into effect, although the principle of it has long been quite 

 familiar to me, as it was discovered in 1794, and published 

 by Count Rumford in his Essay on the Propagation qf Heat 

 in Fluids. (Essay vii.) 



Eight years ago the hot-houses here had become old, and 

 the flues were so defective, that we suffered much injury by 

 the escape of smoke from them. I examined the mode of 

 heating by steam in the neighbourhood of London, and also 

 in other places; but I thought it very imperfect, on account 

 of the employment of metal pipes. Metal transmits heat so 

 rapidl}^, that it is an unfit medium for its conveyance. 

 After an experience of eight years, I can confidently affirm 

 that stone is greatly preferable ; and although the mode in 

 which it is employed here may admit of improvement, yet it 



