FRUIT AND KITCHEN GARDENS NEAR PARIS. 29 



return, for hot water. The circumference of the six-inch pipe 

 is to the sum of the circumferences of the four-inch pipes as 

 18-857 to 25-142, or within a fraction of 15 to 20. It there- 

 fore appears that about one-fourth less metal is required for the 

 flue than for the pipes ; and if it were possible to get the larger 

 casting at the same rate per Ib. as the smaller, the cast-iron flue 

 would be, in the first instance, a saving of 25/. per cent. This 

 alone is an important object ; and when the saving of fuel and 

 more effective heating are stated to be the results, certainly no 

 more arguments need be adduced in favour of the plan. It is 

 necessary, however, to make a few remarks with reference to 

 the position of the cast-iron flue. It was stated above that it 

 uniformly ascends along the front. This being the case, the 

 heated air also ascends naturally towards the farther end, thereby 

 causing a less pressure in that part of the pipe next the fire. 

 This part would become excessively hot if the pipe were level, 

 and would even give out a greater excess of heat next the fire 

 than the old flues, iron being a more rapid conductor than the 

 materials of which they were composed. Probably one foot in 

 twenty would be a sufficient^gradient ; those observed appeared 

 to rise more than this. 



M. Truffaut prefers the Queen Pine-apple, because that variety 

 best suits the market, grown to the weight of 2 Ibs. He sells 

 the whole to a fruiterer a little before the fruit is ripe for twelve 

 or fourteen francs each. 



He forces vines in wooden pits or frames 4 feet wide, 3 feet 

 6 inches high at back, and 1 foot 6 inches in front. Heat is 

 obtained from copper pipes and dung linings. The vines in 

 these wooden frames are forced every second year* In such 

 frames strawberries are forced ; ten ranges, each sixty or seventy 

 feet in length, for vines and strawberries cost about ninepence 

 each range per day for fuel, which is wood. The boilers are 

 copper. The varieties of Strawberries forcing were Keen's 

 Seedling, British Queen, and Elton. The latter, although a 

 late variety, is employed with advantage, because it is a great 

 and certain bearer, and answers well for coming in after the 

 other forced sorts, and before those in the open ground. The 

 ranges for forcing French beans are extensive, the variety 

 being the Nain hatif de Hollande. 



Potatoes, the Marjolin, considered the same as the Ash-leaved 

 kidney, had an exceedingly healthy appearance, growing in 

 frames. Those which M. Truffaut forced last season had no 

 disease ; but those he grew in the open ground were much 

 diseased. 



M. Truffaut expressed himself as having been much gratified 

 with his visit to England some years ago, when he had an oppor- 



