THE ORCHID REVIEW. 87 
PIPE THERMOMETERS IN ORCHID HOUSES. 
SINCE the commencement of this year, I have been carrying out some 
experiments to satisfy myself as to the maximum heat of. the water in the 
hot-water pipes required to give the: best results in the cultivation of 
Orchids, especially during the winter months, when there is very little 
sunshine, and we have to rely on pipe heat alone for the required tempera- 
tures. In order to experiment in this direction, I had two thermometers 
«fixed in two of the mains connected with my boilers, these thermometers 
being specially made to screw into the pipes, so that the glass bulb of the 
thermometer (which is enclosed in a brass tube) projects into the water 
about an inch, and so registers the heat of the water accurately. I have 
taken my registrations three times a day during the month of January, and 
now send you the particulars, in the hope that the results may interest you, 
I send two sheets of registrations, the one from my warm Cypripedium 
house (in which I grow all the Cypripedes that require warm treatment), 
and the other from a Dendrobe house, where these Orchids are rested 
during the winter months. I think the sheets will explain themselves, but 
may say that the columns show the date, the conditions of the weather, 
the maximum day, and the minimum night temperature, out of doors, 
together with the morning, noon, and evening registrations of the heat of 
the water in the pipes, and of the atmosphere of the houses. 
‘I may explain that my aim has been to obtain a maximum heat of 65° 
Fahr. in my Cypripedium house during the day, and a minimum of 60° 
during the night, while in the Dendrobe house 50° and 55° have been the 
minimum and maximum aimed at. So far as the results go, it would 
appear that 120° is the highest and most suitable heat of water to give the 
maximum of atmospheric heat, at noon, in the Cypripedium house, while a 
water heat of 115° will produce the required air temperature of 55° in the 
Dendrobium house. If the weather be sunny the air temperature is allowed 
to rise, or the water heat is lowered by closing the boiler damper, or shutting 
off a range of hot-water pipes. . 
I find that by means of these pipe thermometers the men Bey a ak 
better idea how to-manage their fires, while I can detect irregularities in 
stoking whenever I walk through the houses in which these thermometers 
are fixed. I ad continuing these registrations during the present 
year. 
O. 0. Wrictév. 
Bridge Hall, geal 
TWe. omit she page of -statintios,:. as the. letter clearly is the 
general principles, and details would naturally vary according to the 
situation of the house and the amount of piping init. The value of the 
system appears to be that an intelligent stoker, by noting the fluctuations 
