Jannary 26, 1871. ] 



JOUKNAL OF HORTICULTURE AND COTTAGE GAEDENER. 



69 



the purpose of military defences — viz., a8 cheranx-de-frise. Their 

 caltivation ia of the greatest importance in desert and barren countries, 

 as they delight in the very driest soils, and not only produce an 

 abundance of edible fruit, but also a considerable quantity of firewood. 

 These Tunas hedges are also used for breeding the American Cochi- 

 neal insect, and are planted in some provinces of Mexico to a very 

 great extent for this purpose, as formerly the exportation of cochineal 

 from that country was very large." — G. 



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SLOW-COMBUSTION STOYE. 

 As some oj my friends have had stoves made upon a model 

 I devised about two years since, and as they report very favour- 

 ably of them, I think it possible some of your readers may be 

 interested, and perhaps helped, by an account of my experience. 

 About two years and a half ago I constructed a greenhouse 

 entirely of wood and glass ; length 10 feet 6 inches, breadth 

 9 feet, height 9 feet to the centre of the pitched roof. The 

 question of heating it arose as the winter drew on, and I gave 

 an ironplate worker an order for a stove, the performance of 

 which I will presently describe. Having improved upon the 

 first model, I append a sectional drawing of a better form which 

 has been made recently. :,^3;7i7iii;-: 



The body of the stove consists of a cylinder of sheet iron 

 6 inches in diameter, in fact a length of 6-inch iron pipe. Its 



height is 2 feet. The bot- 

 •. torn has one opening in 

 the centre, admitting air 

 to a piece of gas-pipe li 

 iach in diameter, 4 inches 

 long, and capped at top. 

 Upon the screw at the 

 1 iwer part of this gas-pipe 

 are two nuts, one 'fitting 

 above the bottom and the 

 other below ; these fix the 

 gas-pipe into its place. 

 The upper part of this 

 pipe (not the cap), is bored 

 by fourteen holes about 

 one-quaitr of an inch in 

 diameter. The lid of the 

 stove fits loosely ; and out- 

 side the pipe and around 

 the upper part is secured, 

 by soft solder, a zinc gut- 

 's^ ' ' ^i' ter about three-quarters 



I \ of an inch deep and the 



■"^ *~ same in width. This, 



when the stove is in use, 

 is filled with water, and 

 effectually prevents the 

 escape of any of the products of combustion. It is desirable to 

 tin, as it is technically called, that part of the pipe against which 

 thewater rests, as it will prevent oxidation. A flue-pipe, 6, 

 IJ inch in diameter, proceeds from the stove and contains a 

 throttle, c— that is, a flat circular piece of metal, of the same 

 diameter as the inside of the flue, turning upon a pivot, so that, 

 when its transverse diameter is in the same direction as the 

 length of the pipe it does not impede the escaping gas, but 

 when turned across the pipe it closes it. The chimney of my 

 stove is of zinc, and travels from the centre of the end to the 

 opposite extremity of the side of my house, and descends 

 gradually daring its whole course. 



I will now endeavour to explain the philosophy of the ar- 

 rangements I have pointed out. The fuel chosen is charcoal 

 broken smaU. Charcoal may be obtained of the requisite size 

 for this stove at a lower price than in larger lumps. The char- 

 coal in burning is converted into carbonic acid and ash. The 

 ash, being that part of the wood from which the charcoal was 

 made, which the tree took up from the earth, is a most valuable 

 manure, and adds wonderfully to the power of potting soil. 

 This ash faUs to the bottom of the stove, and so leaves free 

 the holes by which air is supplied. The carbonic acid formed 

 by the union of the oxygen of the air with the carbon of the 

 charcoal is about one and a half of the specific gravity of the 

 atmosphere, and so when cold it faUs ; but "as it is produced in 

 the stove at a high temperature, it is expanded and rises. As 

 It passes into the chimney it cools, and, becoming heavier than 

 the air, tends to descend ; for this reason the chimney is made 

 to slant downwards. It thus assists the draught, and acts also 

 as a damper ; for if the fire should be dull the chimney pours out 

 its heavy well-cooled charge of carbonic acid, and so draws up 



the fire ; but if the fire be burning fiercely the heat is not 

 expended so readily, and the carbonic acid when it has reached 

 the chimney, still tending to rise, has to be forced out by the 

 rising hotter air in the stove, and this checks the combustion. 



The object of the throttle has already been hinted at. By- 

 its means the fire may be governed as easily as an ordinary 

 gas-burner. 



When my stove was finished I lighted and filled it, and turn- 

 ing the throttle very low left it untouched, watching how long 

 it would burn. It continued alight for a hundred hours. The 

 amount of heat given was very small, but my experiment was 

 to ascertain the lowest combustion attainable. In ordinary 

 frosts I light my fire about nine at night, and next morning 

 put on about a quart of charcoal, turn the throttle very low, 

 and about seven in the evening pour the contents of the stove 

 into a fine round garden sieve. I riddle the lighted contents, 

 and so get rid of the dust, pour back, and refill ; and I repeat 

 this day by day with what variations the weather may neces- 

 sitate. The fire has never once gone out without my intending 

 it during two winters, nor have my plants suffered from frost 

 all through this severe weather owing to the stove failing, 

 although I have had no mats on the roof, and my greenhouse 

 is 100 feet at least from any building, so that it is very much 

 exposed. 



There are other points which might need explanation, such aa 

 the method of lighting, the reason why plate iron will not answer 

 for the chamber supplying air, cost of fire, &c. ; but as I must 

 be trespassing on your space I will leave these matters, pro- 

 mising to take them up should any of your readers need in- 

 formation respecting them. — F. Cheshike, A.C.P. 



a. Gutter. &, Chimney. 

 c, Throttle valve, i. Handle. 



DECISIONS OF THE FRUIT COMMITTEE OF 

 THE ROYAL HORTICULTURAL SOCIETY. 



We are much surprised at reading the report of the Com- 

 mittee's jadgment upon the Main Crop Potato at the last meet- 

 ing, and we would like to ask under what conditions the Pota- 

 toes are placed before the Committee, as all the varieties of 

 this important vegetable lately submitted for their inspection 

 appear to receive uniform condemnation. The system of boil- 

 i ing at a place where cooking is not carried on to any extent 

 appears to us to be objectionable, and we think the Fruit Com- 

 mittee should lay down some specific course of action. 



We recommend, as the fairest way, that a notice be given, 

 " that no Potato will be judged until it has been grown in the 

 Chiswick trial grounds." Under the present conditions even 

 this trial is no safety, because our Main Crop Potato, which is 

 really a first-class variety, was grown at the Chiswick trial 

 grounds in 1868, and we have reason to believe was then con- 

 sidered to be one of the best, if not the besf^ of the red-skinned 

 class. We should like to ask Mr. Barron, the garden super- 

 intendent, who grew it, to write his opinion of it as grown and 

 tested by him at Chiswick. We fail to see how a Potato can 

 change its character in two years, and we know that when 

 tested on Wednesday, the 18th, the dish ol Potatoes had such 

 an appearance when served up, that no gentleman would 

 permit them to be placed on his table. We are strongly of 

 opinion that a bad variety cannot be too soon condemned. We 

 are also equally sure that all varieties should have a fair and 

 proper trial. Hiving this in view, we should like to ask why 

 the report of the Chiswick trial has never been made public ? — 

 Jaues Caetee & Co. 



WORK FOR THE WEEK. 



KITCHEN GAKDHK. 



Lose no opportunity of bringing the ground into a good 

 working condition for the crops which must soon be committed 

 to it. A generous soil always pays well for the extra labour of 

 frequently turning it. Asparagus, a fresh bed should now be 

 planted ; a very considerable proportion of leaves should be 

 used in the formation of the bed. The beds in cutting should 

 have air freely admitted during mild weather. A crop of Beans 

 should be planted in boxes or pots, which should afterwards be 

 placed in a forcing house. At the same time a crop should be 

 planted in the open ground where it is in good condition. 

 Make a sowing of Early Horn Carrot on a sUght hotbed, to- 

 come in for a first crop. Where the soil is light and dry, a 

 sowitig may be made on a south border. Those who are short 

 of old Onions, or who wish to grow some of a large size,- should 

 now sow some White Spanish in a box, which should be placed 

 in a forcing house. The UDdergronsd sort lasy now be nlanfcodi 



