Febraary 13, 1874. ] 



JOURNAL OP HOBTIOULTURE AND COTTAGE GABDENEB. 



147 



window, I am most anxious for a few hints as to any addition 

 it would be possible to make under these unfortunate ciroum- 

 stanoes. I may add that the garden is on a hill, and much 

 exposed to the west and south-west. The kitchen garden 

 presents the same difficulties, and although I have sown Peas 

 over and over again they never pay for the trouble. I have 

 a good wall fronting the west, and on this I have occasionally 

 a few Pears. Cherries I can make nothing of, except a small 

 crop of Morellos on a south wall ; the same with Apples and 

 PlumB, although we have many trees. — A Lady GAnDENEit. 



[Many besides our correspondent would be benefited by 

 Buch information as she seeks for, and we will readUy give 

 insertion to communications on the subject. — Eds.] 



THE VALUE OF FUEL.— No. 2. 



It was shown in the last paper on this subject that the 

 theoretical amount of heat yielded by different species of fuel 

 was enormously modified in practice by the nature of the 

 arrangements for combustion and for the utilisation of the heat. 

 It is i^uite possible, in consequence, that the cheapest of fuels 

 might become the dearest in use. Still, before considering 

 the best mode of extracting the heat, it will be as well to 

 ascertain which species of fuel is really the most economical 

 at existing prices, supposing its fuU degree of heat could be 

 employed. The prices will of course vary according to local- 

 ities, but each person may correct the figures for himself. 



Taking coal at 20s. per ton, the price per pound is about 

 one-ninth of a penny. A ton of coal yields from 55 to 80 per 

 cent, of coke — according to its quality — or say on an average 

 fifteen hundredweight, which is about the weight of a chaldron 

 of thirty-six bushels. It may be convenient to remember that 

 as coke swells in making and thus occupies more bulk than the 

 ooal from which it is made, its weight is somewhere about half 

 that of the same bulk of coal. The price also varies, but 

 generally it is about 30s. per ton, or say one-sixth of a penny 

 per pound. Of gas about 9500 cubic feet are made from eacla 

 ton of ooala — it is of specific gravity from -50 to -55 (air being 

 10, and 13J cubic feet of air weighing 1 lb.), and this quantity 

 of gas therefore weighs about 365 lbs. At 4s. per 1000 cubic 

 feet, as furnished by the companies, its cost is therefore about 

 1 Jd. per pound. Petroleum at 2s. per gallon costs about 3d. per 

 pound, and colza oil Gd. per pound. 



If, therefore, we range these substances according to the 

 cost of the quantity of each required to yield 10,000 units of 

 heat we shall obtain the following results in pence and deci- 

 mals of a penny : — 



Colza 8-3 I Coke '15 



Petroleum 1-5 Coal (Household) -OS 



Gas '5 I 



Or, iu other words, a given amount of heat which can be 

 obtained from coal of ordinary quality for Id. would cost 

 nearly 2d. if derived from coke, dd. if derived from gas. 

 Is. dd. if derived fi'om petroleum, and 3s. if derived from 

 colza oil. 



Obviously, then, coal is the fuel which economy points to, 

 provided only we can burn it economically. The fact that 

 other descriptions of fuel ever compete with it only shows the 

 points in which we mismanage it. Coke yields no waste in 

 the form of smoke, and gas no waste in the form of uncon- 

 Bumed carbonic oxide, while the oils, if used, are generally 

 employed in lamps, or in an apparatus which extracts the 

 whole of their available heat. Thus dealt with they may 

 easily become more economical than coal, thrown in masses 

 into a furnace which vomits forth unburnt gas and soot, and 

 which is placed beneath a boiler so small as to let nine-tenths 

 of the heat escape into the chimney. But these errors may 

 be remedied. A wide and long range of furnace bars on which 

 the fire may be kept thin and bright, and the coal gradually 

 coked as it is pushed forward from the front, while air enough 

 is admitted to consume fully the hot gases at the back, the 

 admixture of clay balls to prevent caking and to make com- 

 bustion slower while equally perfect, and a large increase of 

 boiler-surface exposed to the flame and effluent gases, aided, if 

 necessary, by the addition of a flue through which they may 

 give off their heat in the house before entering the chimney, 

 would enable us to use coal with the certainty of giving the 

 full advantage which its real heating power and low price can 

 afford. 



But it must be kept in view that to permit this result space 

 is absolutely essential. It is true, indeed, that whatever the 

 fuel a large boUer-suiface is alike indispensable, for iion can 



only transmit a fixed amount of the heat applied to it iu a 

 given time, and if we want more heat we must increase the 

 extent of iron exposed. But, over and above this, coal needs 

 space for its combustion, for its nature is such that in a con- 

 fined space it distils instead of burning. Now a large space is 

 not always to be had, and in such cases either coke or gas may 

 prove more convenient. But I may point out that in burning 

 coal another element of great value is wasted, and might be 

 preserved without loss of heat. Your readers are all aware 

 that in gasworks a large amount of ammoniacal liquor is 

 produced, the value of which as manure is immense. Each 

 ton of coal (if of average composition) yields thus about 30 lbs. 

 of ammonia, the money value of which at present prices is 

 about 25s. I have shown in a recent number of the Agricul- 

 tural Gazette of what enormous importance to the country it 

 would be to save this waste, and I have also suggested that 

 the general use of private gasworks would be a measure which 

 would do something in this direction. Attached to gardens 

 such apparatus would cost Uttle trouble, and indeed in many 

 establishments they already exist. But the resulting gas need 

 not be purified when intended only for heating pm-poses (al- 

 though it might be if desired also for lighting), since it would be 

 equally available for heating although not thoroughly purified. 

 In ordinary gasworks about one-third or one-fourth of the 

 coke produced is used for heating the retorts in which the gas 

 is made, but in gardens a large proportion of the heat thus 

 expended could be recovered, either by the use of a flue, or of 

 a boiler to utilise the heat from the furnace in which the retort 

 is heated. The practical result would be that each ton of 

 coal would yield about half a ton of coke for combustion iu 

 the regular stokeholes (over and above the coke employed in 

 the retort furnace), about 9000 cubic feet or 350 lbs. of gas for 

 use in heating whenever found convenient, and at least 20s. 

 worth of ammoniacal liquor tor application to the garden crops. 

 In future papers I shall deal with the arrangements for con- 

 veying the heat to the places where it is required, and the 

 amount of heating surfaces necessary for given amounts of 

 coohng surfaces. — J. Boyd Kinneab. 



RAINFALL AT NASEBY WOOLLEYS, 

 NORTHAMPTONSHIRE. 



1873. 



January . . . 

 Februai*y . 

 March . . . 



April 



May 



Juue 



July 



August . . . 

 September 

 October . . . 

 November . 

 December . 



Total . 



-H. Habeis. 



Number of days 



ou which ) 

 rain or snow fell. - 



Total amount. 



14 

 13 

 12 

 12 

 13 

 9 

 14 

 15 

 12 

 10 

 12 



142 



Inches. 

 1.54 

 1.30 

 2.69 

 0.70 

 2.67 

 4.08 

 1.88 

 2.62 

 1.02 

 2.13 

 2.38 

 0.52 



- 23.43 



NASH COURT. 



I HAVE only lately seen an interesting communication on 

 Nash Court in Kent, from Mr. J. Eobson, in the number of 

 The Jouknal of Hobticulture for October 9, 1873. As the 

 great grandson of the last Thomas Hawkins, of Nash Court, 

 and a party to the sale of this old family place to Mr. Lade, 

 the present owner, I send you a correction which you may like 

 to notice. There are in Kent two estates, both of which bear 

 the name of Nash Court — one in the Isle of Thanet and the 

 other near Boughton-under-Blean, Faversham ; and these have 

 been inadvertently confounded in the history of Mr. Lade's 

 house. The descent, I believe, is correctly stated through 

 various families down to the Turners, of the Nash Court in 

 Thanet, which, as long ago as when Hasted wrote his history 

 of Kent (1790), had ceased to be a gentleman's mansion, and 

 was used as a farmhouse and granary. But the error is in 

 applying that descent to Nash Court at Boughton. That estate 

 never passed away (for more than five hundred years) from the 

 Hawkins family. It came to them by the marriage of Joan 

 de Nash with Andrew Hawkins, as appears by the inquisition 

 iwst mortem taken 17 Edward HI. (1313), It descended from 



