u 



JOUENAL OF HORTICDLTUEE AND COTTAGE GAEDENEB. 



I January 8, 1874 



old. No fresh tree or Rraft had been imported into it for at 

 least seven years, and the nearest fruit garden was twelve 

 miles distant. — {Communicatcdby Vf.S'wsi.B, Canterburij,N.Z.) 



HEATING— FUEL.— No. 2. 



Gas having the greatest heating power of all ordinary com- 

 bustible substances, it must necessarily be the best for heating 

 hothouseB or greenhouses by the circulation of heated water in 

 iron pipes. I make no question of the superiority of gas over 

 coke and coal, but whether it is equal in cost, or less or more 

 expensive than either of these two, I am not in a position to 

 ascertain, therefore I ask for information on this head. 



In heating by gas all the heat generated by the combustion 

 of the fuel can be utilised. The boiler or apparatus being 

 entirely within the house, we not only secure the heat of the 

 water in the pipes to be given ofi by them, as in other boilers 

 heated by coal or coke, but the heat that is given off by the 

 surface of the boiler itself, which in some cases, as when the 

 boiler is in a shed outside the house, is equal to as much 

 heating surface as would warm one or more of the compart- 

 ments heated by the hot-water pipes. The great fault of the 

 majority of our hot-water boilers is that their setting is heated 

 quite as much as the water in the boiler, and the heat is all 

 the time given off in space outside the structure, and is there- 

 fore sheer loss. No one would, neither do I, advocate the 

 fixing of boilers so as to have the stokehole within a green- 

 house, but I see no objection to having a properly-constructed 

 boiler entirely within the house, yet stoked from tho outside, 

 so that the dust and smoke consequent on combustion may be 

 kept from the plants. To have the boiler within the house is 

 to derive the full benefit of the heat ; to have the boiler out- 

 side is to lose the whole of the heat radiated from the boiler's 

 outer surface, which in some cases is nearly, if not fully, equal 

 to the surface acted-on by the fire. 



Quite different is heating by gas to that by coal or coke. 

 There is no dust or dirt, no frequent attention, the trouble is 

 almost nothing, no cost of carriage of fuel beyond the first pro- 

 vision, no uncertainty of heating, the heat being the steadiest 

 and most constant. On these grounds gas-heating is to be 

 preferred to any other mode. 



The boiler being within the house, and the air which is 

 required for combustion derived from the house instead of 

 from the external air — as in tho case of boilers fixed outside — 

 is this an evil or otherwise ? The heating power being in 

 proportion to the air consumed, and gas being the most 

 powerful agent of all, it may be that we lose as much by 

 taking from the internal warm air for combustion, admitting 

 cold external air to supply its place, as is gained by having 

 the heating power within the house. There may be some loss 

 of heat in this way, for it is only just to consider that the 

 displacing of warm air by cold must lower the temperature in 

 which this takes place ; but is not the displacing of warm 

 vitiated air (as it all is in a confined structure) by the admis- 

 sion of cold fresh air, counterbalancing? This, if an evil, 

 could be overcome by supplying the combustion chamber 

 direct from the external air, moderating the current of air by 

 a screen or screens of perforated zinc, and in this case no loss 

 of heat would be experienced, the fumes of the gas being 

 properly carried-off by a securely-jointed pipe or funnel to 

 the external air. 



It is generally considered that gas as a mode of heating is 

 only suitable for small structures, but the reasoning by which 

 such a conclusion is arrived at puzzles me. Because gas is at 

 present only used for lighting and for heating on a small scale, 

 what have we to be guided by in concludiug it not suitable for 

 heating on a large scale ? Surely nothing but the supply, for 

 if it answer — and there is no question about it — for small 

 houses, it is evident it would do so equally well for large struc- 

 tures. The only thing would be to have larger apparatuses 

 and separate ones for every structure, which is one of the 

 greatest points in favour of gas as a fuel in comparison with 

 either coal or coke. The heating by gas would enable us to 

 dispense with reserve or duplicate boilers, without which it is 

 admitted our very best makes of hot-water boilers are not safe. 

 There is always an anxiety, especially in severe weather, at- 

 tached to heating by one boiler which it is not pleasant to ex- 

 perience, to say nothing of a breakdown of the heating appa- 

 ratus at such a time. By gas-heating we entirely relieve our. 

 selves of the anxiety of a breakdown ; we save the duplicate 

 boiler, equal to the cost of furnishing every compartment with 

 a separate heating apparatus ; we are enabled to dispense with 



a vast quantity of flow and return pipes to and from the boiler, 

 which in many cases are equal to a large extent of heating 

 surface, at times corresponding with the heated surface utilised ; 

 so that a considerable saving of fuel is effected by heating the 

 radiating surface only, none being lost in supply and return 

 pipes. When we add the value of the piping that is taken up 

 in flows and returns, and the necessary elbows and costly 

 valves, it is clear there is a saving in first cost of no mean 

 amount, probably equal to half the first cost of an apparatus 

 for heating each structure separately by gas. 



Then when but little heat is required, the fire that has to be 

 kept going for the heating on the one-boiler system of very little 

 piping is something enormous compared with the work done, 

 so much of it being expended in heating the water in the 

 boiler (which is the same in quantity for a large as for a small 

 extent of piping) and the connection pipes ; so that we are left 

 to wonder why in point of economy we departed from the 

 principle of heating each house separately and adopted the 

 one-boiler system. We cannot get more from the fuel than 

 the heat there is in it ; and how a large furnace should give 

 more heat than four or half a dozen smaller ones, the quantity 

 of fuel being the same, is only to be accounted for by the 

 extravagant manner in which we employ tho fuel, half its heat 

 being expended on the setting ; consequently we have almost 

 as much loss by the setting of a smaller boiler as in that of 

 one six times larger : hence the greater heating power of a 

 large as compared to a small boiler furnace. 



Every house should have its separate heating apparatus, 

 which should have a boiler so constructed that the whole of 

 the heat, less that below tho temperature of boiling water 

 (212'), aiJorded by the fuel, will to the utmost extent be given 

 out and imparted to the water ; and this being the case, as 

 I see no reason why it should not, the necessity or value of 

 the one-boiler system and accompanying dupUcation vanishes. 

 Gas, because it enables us to heat every structure independently 

 of another, because there is no waste of heat or fuel, and 

 because of its certainty and steadiness of action, cleanliness, 

 and easy management, I hold to be the best mode of heating, 

 and therefore preferable to all others. — G. Aebey. 



INFLUENCE 



OF THE STOCK ON 

 AND VICE-VERSA. 



THE SCION, 



[Kssay Read at a Meeting of the American Pomological Society.] 

 Both theory and practice teach us that the relationship 

 existing between the root and the top of a tree cannot be im- 

 paired to any great extent by any artificial intervention of 

 man. The very moment that an inserted bud or graft com- 

 mences to granulate and then unite, that moment the two 

 parts of the embryo tree struggle, as it were, for the mastery. 

 That is, certain idiosyncrasies, inherent either in the branches 

 of the one or the roots of the other, will form a leading feature 

 in the mature plant. Abundant proof of this is afforded by 

 examining the roots of nursery-grown Apple trees, whether 

 budded or grafted. Take, for instance, some well-known variety, 

 as the Bellefleur, and the roots will be found uniformly long, 

 slender, and very fibrous ; other kinds will prove exactly the 

 opposite. If we place a graft of some well-marked variety 

 upon any ordinary stock, say 5 or feet high, in a few years 

 certain peculiarities of the bark will be found extending down 

 from the branches to the body of the tree ; as is instanced in 

 the Newtown Pippin Apple, and Van Mons Leon le Clerc Pear. 

 Another curious feature respecting the influence of the scion 

 upon the stock, is noticeable in some of the so-called " sports," 

 or variegated-leaved plants. 



During the past season [1872] , a Mountain Ash, upon which 

 was budded a variety with variegated leaves, commenced to 

 push forth young shoots from the main body of the tree, below 

 the point where the bud was inserted. In every case these had 

 variegated leaves. Now, in view of the fact that these adven- 

 titious buds were there in advance of the original variegated 

 bud, the presumption is that they were created green, and 

 their normal condition yielding to the controlhng influence of 

 the new branches, caused the change to occur by the flow of 

 sap from above. 



A still more remarkable case than the one above cited, was 

 related some time since. Scione of a diseased Horse Chestnut 

 with yellow leaves were worked upon strong, healthy young 

 trees. Sometime thereafter, upon examining the stocks where 

 the scions had failed, young shoots were found down the body 

 bearing the identical yellow-hued fohage ; and yet, where the 



