December 8, 1870. ] 



JOURNAL OF HOBTICULTUBE AND COTTAGE GASDENEB. 



453 



merit of the gardens ; wherever one turned, order and an ap- 

 pearance of exquisite finish and neatness prevailed. Yery rarely 

 indeed is it that one sees a garden in which there is so little 

 to which exception could be taken ; no object appeared to be 

 eared for at the expense of others, but all were alike most 

 satisfactory. 



To anyone travelling from Derby as I did, a visit to Chats- 

 worth implies a most interesting and enjoyable trip, for the 

 railway from Derby to Eowsley winds through some of the 

 most beautiful scenery of Derbyshire, the bold character of 

 which is very striking. Hills in endless variety present them- 

 selves to the eye; some destitute of vegetation, excepting the 

 olosely-eropped turf, stand out boldly and clearly, rearing their 

 lofty crests in most picturesque contrast to others clothed from 

 base to summit with a compact mass of trees. Now a mag- 

 nificent vista opens out along some pleasant dale, affording 

 glimpses of other hills, with their bold outlines softened into 

 grace by the distance ; and then, as at Matlock Bath, the hills 

 rise in lofty majesty, towering high overhead, clothed in some 

 parts with dense foliage, among which glimpses are caught of 

 picturesque cottages snugly perched on the steep hillside, and 

 of places where the face of the cliff exposes the overlying strata 

 as they dip downwards to the valley. Passing through such 

 scenery as this the mind i3 prepared to thoroughly enjoy and 

 appreciate the refinement and magnificence of Ohatsworth, 

 which impresses one as being altogether, worthy of its exalted 

 position in a county so rich in the beauties of Nature. — 

 Edwakd Lucehuesi, Old Lands, Buxted, Sussex. 



HEATING BUILDINGS BY HOT WATER. 



The proverbially fickle climate of the British Islands (says 

 the Mechanic's Magazine), and the frequent recurrence of a 

 damp and cold atmosphere, make the application of artificial 

 heat to our dwellings and publio buildings a positive necessity. 

 Contrivances for producing an equable temperature within 

 doors are consequently numerous, and in many instances they 

 are of an ingenious character. Perhaps the best mode of 

 accomplishing the desired end, as well as the simplest, is that 

 of causing the circulation of hot water through iron pipes con- 

 veniently disposed for the purpose. Up to a very recent period, 

 however, a considerable amount of hostile prejudice existed in 

 regard to the use of hot r water apparatus, and even now the plan 

 of heating buildings by such agencies is not fully appreciated. 

 Imagining that antipathy to the system arises in many cases 

 from a lack of acquaintance with its peculiar merits, we shall 

 endeavour to explain the principles which govern the aciion of 

 ■hot-water apparatus generally, and furnish some information 

 as to their best form and proportions. In order to do this 

 effectually, we must first glance at one or two of the natural 

 laws which affect the circulation of fluids and gases. That all 

 falling bodies gravitate with the same velocity aDd therefore 

 descend through a certain definite space in a given time, is an 

 •affect of which gravity is the cause. It is from this cause that 

 we obtain the unerring action of the pendulum. To the same 

 source may be distinctly traced the phenomena attending the 

 circulation of hot water through pipes, and this circulation, 

 once created, forces all the water in the apparatus to pass suc- 

 cessfully through the boiler by which it is primarily heated. It 

 is upon the continuous and uniform movement of the water 

 along the pipes that the efficacy of the hot-water apparatus im- 

 mediately depends. Let us, then, inquire a3 to the power 

 which insures this vitality, for without a clear perception of its 

 nature there will ever be uncertainty as to the working of any 

 apparatus of the kind in question. The force which produces 

 circulation arises from the fact that the water in the descending 

 pipe is heavier than that which is in the boiler, or, to put it 

 differently, when heat is applied to the boiler a dilatation of the 

 water within it ensues. The heated particles ascend through 

 the colder ones, whilst the latter descend by reason of then- 

 greater specific gravity, and in turn become also heated. Ex- 

 pansion follows, and this species of action and reaction pro- 

 ceeds until all the particles are equally heated. It follows that 

 the colder the water is in the descending pipe, relatively with 

 that in the boiler, the more rapid will be its motion through 

 the circulating pipes, and hence the diffusion of heat through 

 their pores and into the atmosphere surrounding them. 



Thus much of the general principles which control the action 

 of hot-water apparatus as applied to the heating of buildings, 

 and now as to their particular dimensions and details. These 

 will naturally have to be varied with the character and size of 

 the buildings to be heated. For churches and. largo structures 



of a similar kind, and which have an ordinary number of doors 

 and windows, it will be necessary in devising hot-water ap- 

 paratus to ascertain, first, the cubic contents of the auditorium. 

 Having obtained this knowledge, let the number gained be 

 divided by 200. The quotient will yield the length in feet of 

 4-inch pipe required to maintain something like a steady tem- 

 perature of 55°. For smaller apartments, as, for example, 

 dwelling houses, &c, the cubic measurement divided by 150 will 

 furnish the proper length of 4-inch pipe. These simple rules, 

 which are the result of extensive practice and careful observa- 

 tion, may be safely relied upon, unless under very exceptional 

 circumstances, and which, of course, would have to be duly 

 considered by the constructor of an apparatus intended to meet 

 them. 



In reference to greenhouses, conservatories, and buildings 

 of a like character, where the temperature should reach a 

 mean of 60°, the sum of the cubic contents divided by 80 will 

 give the length in feet of 4-inch pipe required to produce the 

 desired effect. Forcing houses, again, must have special cal- 

 culations made for properly heating them. Nothing short of a 

 uniform temperature of 70° to 75° will suffice for. such places. 

 In order to insure this the measurement, a3 before suggested, 

 must be divided by 20, the quotient being the length of ciicu- 

 lating pipe required. For gaining yet higher temperatures, 

 lower divisors will have to be employed, and if smaller pipe3 

 be determined upon, the length must be proportionately in- 

 creased. These are points of detail, however, which may be 

 safely left to tire skilled manufacturer who may be intrusted 

 with the making of hot-water apparatus for special purposes. 

 Our own data may betaken as the base of calculations for econo- 

 mically and effectually heating buildings by means of hot water. 

 We are aware that some horticulturists have adopted the 

 plan of heating their forcing houses io a much higher tempe- 

 rature than that indicated above, and of allowing a greater 

 amount of ventilation than is usual. By aid of such arrange- 

 ments, it is said, a finer fruitage is obtained, but there is no 

 doubt that this course involves increased expense in the first 

 cost of the heating apparatus, together with a large augmenta- 

 tion in the subsequent daily consumption of fuel for working it. 

 An important consideration to the horticulturist and flori- 

 culturist is the waste of heat through glass roofs and walls. It 

 has been found, from a course of carefully-made experiments, 

 that 1 square foot of glass will cool 1.279 cubic feet of air as 

 many degrees per minute as the internal temperature of the 

 house exceeds the external temperature. Thus, if the differ- 

 ence between the internal and the external temperature be 

 30°, 1.279 cubic feet of air will be cooled 30° by each square 

 foot of glass in the building which is exposed also to the outer 

 atmosphere. It will be admitted that this faat should be 

 allowed its due weight in contriving hot-water apparatus for 

 houses wholly or partly constructed of glass. Of course, in 

 estimating the area of glass, due deductions must be made for 

 the sash frames and woodwork by which the panes are sur- 

 rounded. If the frames and sashes be made of metal, the 

 radiation and consequent loss of heat through them will be 

 equal in extent to that which results from the glass itself. 



The quantity of air to be heated per minute, 30 far as con- 

 servatories and forcing houses are concerned, should not be 

 less than l£ cubic feet for each square foot of glass which the 

 building contains. When the quantity of heated air required 

 has been thus ascertained, the length of pipe may be determined 

 by the following formula : — viz., Multiply 125 by the difference 

 between the temperature at which the house is proposed to be 

 kept (when at its maximum) and the temperature of the ex- 

 ternal air, and divide the product by the difference between the 

 temperature of the pipes (200°) and the proposed temperature 

 of the room. Then the quotient multiplied by the number of 

 cubic feet of air to be heated per minute, and its product 

 divided by 222, will give the number of feet of 4-inoh pipe to 

 yield the desired effect. 



CLIMBING FERNS.— No. 4. 



STENOCHLfflNA. 

 A family of Ferns comprising but few species, and nearly- 

 allied to Lomaria. They have long, smooth, creeping rhizomes, 

 which fasten themselves to the stems of trees or other objects, 

 and by which, in a state of nature, they climb to considerable 

 heights. They produce fronds of two forms having free-forke 

 veins, which spring from an obscure vein running parallel wi 

 the midrib, and on which in the fertile fronds the sori are situ- 

 ated, but, through their being so much contracted, these appea 



