AKD CONSERVATORY. 31 



the difference in temperature is greatest between the point of 

 departure and the extremity of the pipes. What do we re- 

 quire, then, to obtain a good result ? That the water in the 

 pipes obtains as quickly as possible the temperature required, 

 and preserves it for the longest possible time. The Thermo- 

 stat-Thermosiphon realises these conditions." 



Lastly, we are bound to mention Musgrave's Slow Com- 

 bustion Stove, which is a stove simply, and not a boiler. It 

 merits mention, because it is the only thing of its kind we 

 would, without fear, place inside a plant house. It must be 

 understood that we do not recommend either the introduction 

 of a gas-flame or a fire of any kind into the same enclosure 

 with any kind of plants, but it is our business to provide for a 

 variety of circumstances, and it is with pleasure we are en- 

 abled to testify, from observation and experience, that Mus- 

 grave's stove is the least harmful amongst many contrivances 

 recommended for placing inside a plant house, and at the same 

 time easily managed, economical, and efficient, as a diffuser of 

 beat. It is manufactured by Messrs. Musgrave Brothers, High 

 Street, Belfast, and the prices range from 90s. upwards, ac- 

 cording to size. For a house of one hundred to two or three 

 hundred square feet of surface or more, this stove may be em- 

 ployed with safety, and in the case of a large house two or 

 three stoves of small size would be more useful than a single 

 large one. A 90s. stove will suffice for a house measuring 

 twenty-five or thirty feet by eight or ten feet wide, but for any 

 smaller sized house it is not suitable at all. The small upright 

 charcoal stoves that are often used to protect miniature green- 

 houses are Defter than nothing if carefully managed, and that 

 is all that can be safely said about them. 



Mr. Rothney submits, for the amusement of those readers 

 of this work who are inclined to speculations in engineering, 

 the subjoined plan of a self-acting Thermostat. The descrip- 

 tion is as follows : 



The expansive effects of heat on liquids is well known. 

 Water when heated expands in the following ratio : — At 40° 

 it is at its greatest density ; at 65° it increases ^^^ part ; at 

 100°, -jljj part ; at 140°, X part ; at 180°, J-^ part ; at 212°, 

 -^■j part. This being the case, we have a power which can be 

 applied for regulating the temperature in hothouses, by causing 

 the hot water in the pipes to remain at or not increase above 

 a certain temperature desired, also at the same time storing up 



