7?6 REMARKS ON WOOD AND METAL. 
ver injured, though I have always fruited in metal roofed pits, the 
leaves never had what Mr. Mc. Murtrie calls a " yellow hue" when 
in contact with the rafters, nor was their appearance unhealthy any 
more than those grown under wood. Was the reason J. Sahine, 
Esq. did not publish the letter in the Society's transactions, 
which Mr. Mc. Murtrie sent him, because the opinions of the 
writer were considered ill founded ? I one day met with the oldest 
gardener in Derbyshire,* who told me he had the care of one of the 
first metalic hot-houses that was erected, and he said, he never ex- 
perienced any evil effects from them. To return to my experiment 
which Mr. E. H. says is founded on eiTor ; he remarks, that by my 
plunging the wood and iron in water, nothing else could be expected 
but that they would be equally heated, and the reason brought for- 
ward is, that there would be a giving and receiving of Caloric, till 
they were all three of an equal temperature. I beg to state, that 
my experiment was too accurately taken, to admit of the water being 
affected in any other way than by the metal and wood, the water was 
placed in two different cellars perfectly unconnected with each other, 
but both of an equal temperature with the water placed in them ; the 
metal and wood were both immersed at the same moment, and when 
I examined the thermometer, the temperature of one was no higher 
than the other. How could there be a giving and receiving of Calo- 
ric, except what proceeded from the metal or wooden rods immersed ? 
Supposing, however, that metal hot-houses, when painted, were 
greater conductors of Caloric than wood, and the heat of the hot- 
houses was thereby raised, could not every evil be easily counter- 
acted, by admitting a little more air ? how then could pines, vines, 
or any other plants be injured by heat arising from a metallic roof. 
I see no reason why these structures should be brought into con- 
tempt without just cause, or my opinions ridiculed without a proper 
foundation, by what are called Caloric experiments. 
J. Cur. 
July ISth, 1832. 
* Our correspondent alludes to Mr. Stafford, whose opinion will be found, 
page 294. 
