50 



POLMAISE METHOD OF HEATING HOTHOUSES. 



mode of diffusing artificial heat — those very means by which 

 your most splendid results are obtained. 



In July, 1844, a communication appeared in the ' Gardener's 

 Chronicle' from Mr. Murray of Polmaise (Stirlingshire), stating 

 that he had heated a .vinery by merely a circulation of air, pro- 

 duced by the well-known principle that hot air is lighter than 

 cold air, and that therefore, if a stove is placed in a chamber, 

 and a drain is made below the level of the floor of a vinery lead- 

 ing into this chamber, and another passage at a higher level is 

 provided from the chamber back to the house, the entire air of 

 the house will gradually flow through this warm chamber and 

 become heated ; that by allowing fresh external air to pass also 

 into the cold drain under control, any required amount of fresh 

 air could be secured and heated before mixing with the general 

 atmosphere of the house ; that moisture might be supplied by 

 means of passing the hot air over a blanket, kept moist by 

 strands of worsted hanging upon it from a water-trough, and con- 

 ducting the water by capillary attraction, its amount being regu- 

 lated by the number of strands employed ; that on these princi- 

 ples, by means of one of Haden's powerful stoves, he had suc- 

 ceeded in obtaining most excellent grapes, at much less cost than 

 by any of the usual means, without the use either of flues or hot- 

 water pipes ; and he concluded by stating, that all who had seen 

 his vinery expressed much admiration both at the plan and its 

 effects. I will not dwell upon the manner in which this commu- 

 nication was received by some of the first practical men near the 

 Metropolis, — the more than insinuation, that as Mr. Murray's 

 grapes were ripe in September, the vinery was never heated at 

 all, — the sly jeer at the " wet blanket " and the " hole in the 

 wall," — the bold assertion that it " must fail" or " prove waste- 

 ful ;" — suffice it to say, the discussion .became personal and 

 offensive, and was wisely put an end to for a time, and those 

 who abused a principle that they either did not understand or 

 care to investigate, and derided a plan they never tried, must be 

 content to look back upon this uncalled for display of their own 

 ignorance. Nothing particular transpired on the subject till the 

 close of the last year, when public attention was again called to 

 it, and doubts as to facts, strong opinions, and prophecies of 

 failure, were again expressed ; there was no attempt on the part 

 of the opponents of the system to investigate its principles and 

 prove them erroneous ; neither did Mr. Murray, or the one or 

 two persons who advocated it, make any attempt to prove its 

 principles correct, to 'investigate fully their results, or to show 

 that the end Mr. Murray had obtained was only to be expected 

 from the means he had employed ; the facts were denied by 

 some, and those who insisted on them seemed unable to explain 



