248 



JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. [ September 26, 1872. 



look for immediate effect, for its progress for some years after 

 planting is tardy, even in the most favourable situations, but 

 once established, and a fair start made, it grows as quickly as 

 most. The tree here is one of the finest in the grounds, of a 

 deep dark green hue, with a conical outline, almost as close and 

 as true as if pruned into that shape, though the knife has 

 never been used. Its close compact branches resting on the 

 ground have killed all herbage as far as they extend. I shall be 

 glad to learn the height of specimen trees of this kind in other 

 places. 



Picea cephalonica. — This differs from the preceding in its 

 leaves being longer and more pointed, and the habit lower. 

 The largest tree here is 50 feet high; it is also branched to the 

 ground much wider, hut not so densely as P. Pinsapo. It was 

 planted in 18-14, and has coned several times, the cones being 

 somewhat smaller than those of the Silver Fir, but more in 

 clusters, and often covered or nearly so with resin. Like 

 P. Pinsapo and many others of the Picea family, it is slow in 

 making a start, but grows fast enough after. 



Picea nobilis, 40 feet high, also planted in 1S44, lost its 

 leader in 1847, and was eight or nine years without one, when it 

 pushed two, and, one being taken away, the other is as straight as 

 a ramrod, and in every respect unif orm. The tree has for several 

 years borne a great number of very large cones, often more than 

 a dozen in a cluster, with some good seed in them, but the bulk 

 abortive. It is a fine tree, its silvery hue attracting everyone's 

 attention, while the huge well-formed cones are very con- 

 spicuous. For several years its growth upwards averaged fully 

 3 feet, but it has not beon so much since it begun to bear cones. 

 It is, nevertheless, a fine tree, but I believe there are many 

 finer, the situation possibly being too dry for it. 



Picea Webeiana. — The tree is 37 feet high, and was planted 

 in 1844. I do not mention it as being of any remarkable size, 

 but to ask for information, as it is the only specimen amongst 

 several which is at all healthy, and is not by any means so 

 robust as many other species near it. We have had several 

 trees that have succumbed altogether or nearly so. "When in 

 health its appearance is good ; its dark green leaves are more 

 silvery underneath than most kinds, while its noble cones of a 

 rich purple black, so widely different from everything else, give 

 it a claim to attention which no other species possesses. It is, 

 however, delicate ; its young shoots are nipped with spring 

 frosts, and it often loses its leader, so that it is seldom a good 

 tree is met with, and it is possible the specimen here mentioned 

 may be as good as the generality. It is not a tree that. I would 

 recommend, except for some special situations, and must leave 

 to others the task of selecting them. 



Picea lasiocakpa. — This is nearly 17 feet high, and was 

 planted in 1865. It is a promising tree, and with P. Lowii and 

 Parsonii, which I take to be all one, it is the largest-leaved of the 

 Picea^. The leaves being also curved upwards (awl-shaped), 

 differs much from those of P. Nordmanniana, which curve the 

 reverse way, besides presenting other points of distinction. The 

 tree is not so densely clothed with foliage as the last named 

 species. 



Picea Nobdmanniana, planted in 1S65, is upwards of 12 feet 

 high. It appears to grow fast, and is a desirable tree, but the 

 specimens here are small, and my only purpose in alluding to 

 it is to inquire if when it attains greater age it resolves itself 

 into the common Silver Fir. I have heard of this being the 

 case, but am not able to offer any opinion myself on this point, 

 as all the specimens here are sufficiently different in their 

 present condition to entitle them to be considered to belong to 

 a distinct name. 



Picea hagnifica, P. aaiabilis, and P. grandis. — We have 

 specimens of these and other species, but not very large ; and 

 the distinctions amongst them not being clearly defined, I 

 refrain from mentioning them further. 



Taxodiuji seaipervibens, 37 feet high ; planted in 1852. A fine 

 tree, very hardy, and not particular as to soil, as we have more 

 than one specimen succeeding tolerably well, growing in the 

 most unpromising position possible. Its thick spongy bark is 

 singular. — J. Roeson. 



(To be continued.) 



HEATING BY HOT WATER AND HOT AIE. 



I am afraid Mr. Housman and I must agree to differ. He will 

 think me, no doubt, very obstinate, but I fail to be convinced. 

 I speak from experience, having a hot-air heating apparatus 

 which warms a greenhouse next to my house, and also my hall 

 and staircase. The firebox is made of fireclay lumps inside a 

 brick chamber, and I pass the products of combustiou through 

 four rows of 4- inch pipes, three pipes in each row, representing 

 in all 48 feet of 4-inch piping within the chamber. The chamber 

 is fed direct by a current of outer air passing over evaporating- 

 pans. I can obtain plenty of heat, but it is not economical, as, 

 in spite of the 48 feet of horizontal iron piping through which 

 the smoke has to pass, the chimney is too much heated. This 

 I can test very well, as the first part of the chimney after leav- 



ing the pipes in the chamber is through a 9-inch fireclay pipe in 

 a passage in my cellar. There is no error from want of a tall 

 shaft, as the chimney is a very tall one, at least 45 feet from the 

 level of the firebox. 



I find no difficulty in saturating ah-, after it is heated, by 

 passing it over evaporating-pans in the flues or pipes, by which 

 it is conveyed to the place to be heated ; but if cold air is to be 

 drawn by rapid currents over evaporating-pans previous to its 

 being heated, it will be found almost impossible, in spite of 

 Mr. Housman's wet and dry-bulb thermometers, to saturate 

 it. It is of no avail towards extracting the heat from the gills 

 of Mr. Housman's stove to saturate the air after it is heated, the 

 object aimed at being — as moist air is a better conductor of heat 

 than dry — to supply moist air to the stove to extract the heat- 

 As heated air is capable of containing far more moisture than 

 cold air, and the proportion of vapour it can contain increases- 

 in accordance with the heat, so it is easy to saturate air with 

 moisture after it is heated, by supplying plenty of water in the 

 pipes it has to traverse. So little fuel is really required to- 

 create a draught, that the practical loss of heating power in 

 creating the draught is a matter of small moment ; and as high 

 chimneys conduce to more rapid combustion, they are, if not 

 properly attended to by regulating the dampers in the flues, &c.,. 

 more likely to produce waste of fuel than economy, especially 

 in heating horticultural boilers. I likewise do not agree with Mr. 

 Housman's argument, that with the same amount of fuel burnt 

 the draught would be twice as quick, through a 12-feet chimney 

 as a 6. Mr. Taylor's evaporating-troughs are in my mind very 

 different to Mr. Housman's. The house does not depend for its- 

 heat on the air admitted, because the troughs are on the top of 

 the pipes which heat the house. Mr. Taylor's troughs merely 

 ventilate the houses with air which is heated and made moist 

 by passing over troughs before it can enter the house, and he- 

 has a small ventilator in the roof. Theoretically it sounds right 

 — that if air is to be allowed to escape, it is better that cold air 

 should escape rather than hot ; but the fault I find with Mr. 

 Housman's system is, according to his own statements, it is 

 made to depend on rapid currents of air impinging on heated 

 gills of iron, and consequently there must be also a rapid exit 

 of air and consequent loss of heat. This is very different from 

 slowly changing the air in the house h} r means of such appli- 

 ances as Mr. Taylor's. I, for one, do not believe in the necessity^ 

 for plants living in such draughts as some of the modern appli- 

 ances for ventilation are suggestive of ; they do not consume 

 oxygen so rapidly as to require this constant change. 



With regard to the loss of heat in creating a draught, and the 

 impossibility of economising the heat used for that purpose, I 

 can assure Mr. Housman that I have put up a heating apparatus 

 in a church, where there are two rows of 9-inch fireclay pipes 

 set hollow inside a wide flue, which takes the products of com- 

 bustion from a firebox made of 3-inch fireclay lumps. The first 

 pipes from the firebox are iron, and every fourth one of the length 

 of the pipes is iron. The length of these pipes before they enter 

 the chimney is about 70 feet, and so completely do they extract 

 the heat, that the pipes near the fire may be red-hot, and yet 

 there is hardly any perceptible heat in the pipes furthest from 

 the fire before they enter the upright shaft. My object in 

 putting up the heating apparatus was to see whether it was not 

 possible, by means of a long horizontal shaft of fireclay pipes 

 only three-quarters of an inch thick, to economise all the heat 

 caused by the products of combustion. A small stove is used 

 at first at the base of the upright shaft, which is not a tall one, 

 to create a draught, but when once the fire in the heating ap- 

 paratus is going, there is no further necessity for the stove, and 

 the fire is allowed to go out ; the draught is still good, even 

 though the smoke, or rather gases, are so nearly cold by the 

 time they reach the upright, that the waste is practically nil. 

 It is this which leads me to doubt the practical accuracy of Mr. 

 Housman's remarks, that the heat necessary to cause a draught 

 cannot be used for the further purposes of heating; and though 

 there must be a certain waste of heat in a chimney, yet it can 

 be reduced to such a minimum as to prove of no great moment. 

 If anyone wishes to test the relative power of conduction, or of 

 extracting heat from iron, between water and ah-, he has only to- 

 heat two iron bars to the same degree of temperature, and see 

 how much sooner the bar will cool when plunged into water, than 

 if left in air of the same temperature as the water. The true 

 value of water as a moans of conveying heat is, that it has such 

 power of storing up latent heat, and that it parts with it slowly. 

 The best conductors do not necessarily cool the fastest, even 

 if they heat the soonest. However, this is entering on a wide 

 subject — in fact, the discussion between Mr. Housman and 

 myself is one about which there are many differences of opinion 

 both practically and theoretically, though I believe, if we had 

 the opportunity of discussing the matter together, we should 

 agree in the main points at issue, but not in the details. 



I forgot to add that when I spoke of the products of combus- 

 tion playing on to fireclay lumps, I alluded to the fire itself. 

 Mr. H. makes a distinction between the ignited fuel and the 

 products of combustion. I was contrasting the difference 



