Page:The Building News and Engineering Journal, Volume 22, 1872.djvu/93

 ‘ 4 a J TO CORRESPONDENTS. _ [We do not hold ourselves responsible for the opinions of our correspondents. The Editor respectfully requests that all communications should be drawn up as briefly as possible, as there are many claimants upon the space allotted to ‘correspondence.] To Our READERS.— We shall feel obliged to any of our readers who will favour us with brief notes of works con- templated or in progress in the provinces. Letters relating to advertisements and the ordinary business of the Paper should be addressed to the EDITOR, Advertisements for the current week must reach the office not later than 5 p.m. on Thursday. Reorrven.—W. M. & Co.—J. o—wW. J. D—H. & R— B. & TB. S. I—J. M. J. & Sons.—J. 8. G.—E. M.— W. H. L.—H. & Co.—J. U.—G. 0.—E. S.—W. F.—B. F.— FE. ©. R.—G. E. S.—Another Constant Reader.—H. U.— T .N.—J. B. 8. & Co.—P. D. D, M.—The plans and sections in the House Competition ‘must not be coloured. The dimensions of the apart- ments may be “figured on.’ W. W.—If wo inserted your letter, “ Architectural Litera- ture,” in which you ¢riticise the “doggrel” and other matters in the same publication, we might possibly get into a controversy with the said publication, which we have hitherto scrupulously avoided. P, E. M—The reason why the Post-office authorities charged an extra penny is given and commented on elsewhere. We don’t believe the present Government has anything to do with it. We have always found the officials just as officious, whatever men may be in power. Should anything go wrong in any of the departments, wwe know it is somewhat fashionable just now to put the fault on the present Government ; that, however, is unfair. QuANTITY CLERK.—The ‘question about book on land surveying has been answered before. Consult indices. E.P.J—W. E.—T. M., &., &c.—See our remarks under “The Post-office and the Burupinc News.” We shall have something to say on the matter which may assist in preventing such abuse of power in future. We have recently had more than one correspondence with the Post-office authorities in reference to certain mistakes made by them in connection with the English Mechanic, and in each instance they had to apologise and refund. Hovusk PLANNING COMPETITION. — “R, M.” inquires whether, in cubing the house, he is to measure it square to the top of the ridge; or, in other words, whether he is to set down the roof at twice as much cubic space as it really contains? Such a question seems to answer itself; but, to prevent any possible misunderstanding, we say, “Certainly not.” We stated that the houses were to be cubed by finding their solid contents above the ground-line. Cellars may be added without being included in the measurement of space, which is one reason for assuming a somewhat high price per foot cube. If, however, “ R. M.” does not like to call the villa a £2,000 one, he is at liberty to describe it as a £1,500, or even a £1,000 one. The practical point is that it must not exceed 60,000 cubic feet. This condition is binding on all competitors alike, and we see no good ground for making an alteration in it. INTERCOMMUNICATION.—“ Constant Reader,” in reference to our note appended to “ W. H. C..s" reply (2429), «Size of Schools,” says: “Many thanks for the en- couragement given to young men to ask questions in your valuable journal. T have received much instruc- tion from such questions and the answers they elicit, and hope to receive much more.’—An Old Sub seriber” says: “The question put by ‘S. W. J. G.’ was not only a proper but a useful one, and I wish some one had answered it in full to save me, and perhaps others, the trouble of writing for a copy of the ‘Instructions of the Council of Education.’ Besides, possibly these in- structions are not perfect, and hints on them might be found to be servicable.”—" Another Constant Reader,” jn a letter which would occupy at least a half a column of our space, expresses his surprise, &c., that space should be occupied with such trivial matters. Trivial to him, probably, but not to many others; and some, doubtless, would consider his letter trivial if it appeared. Let us all give and take in such matters. ASPHALTE ROADWAYS—‘A ‘Bus Driver” says: “The Editor of the BurnpInaG News would do good service to the public by some notice of the present condition of the asphalte roadway by. Chancery-lane in Holborn. ‘The City Commissioners of Sewers, before wasting more money, would do well to visit the road in question. Mr. Haywood, their engineer, should be attended by a medical man and two trained nurses, as doubtless he would soon become seriously affected by the failure of his pet roadway, and need the services of all three.” Correspondence. + ART v. SCIENCE. To the Editor of the Bumprvae News. Sir,— Coleridge, in speaking of poetry and painting, says: ‘Science aualyses and separates the appear- ances of Nature into their ultimate and indivisible parts; in other words, it deals in abstractions and in certain artificial modes of viewing the world, that are adapted for explaining the order of cause and effect or invariable conjunction therein ; while poetry, painting, and fine art generally deal in aggregates or combinations, and endeavour to produce such combi- nations as are of a harmonious kind. Science deals with a majestic river by resolving it into the forces of gravitation, cohesion, liquidity, optical trans- parency, solubility, &c.; poetry, in common with the fine arts, views it in its full body and entire aspect, and, instead of decomposing, combines it with other THE BUILDING NEWS. objects of the landscape. To harmonise combina- tions of different objects and effects is the aim of art in every region.” Science may be compared to the stalwart oak tree, growing slowly and manfully from the earth; art, to the ivy, delicate and beautiful in form, that clings for support to its trunk. The conjunction is very beautiful, so long as the ivy is not allowed to over- grow and choke the strength that brought it up; there should be no kind of jealousy or opposition between them. When the ivy, vain in its beauty, ignores the means by which it rises to display itself, and forgets its dependent though exalted position, it is time for the woodman to cut away superfluous growth. Nothing seems to me more needed than the scientific and technical education of the artist. Heaven sends us the artist and poet: we can never make them, but when discovered we should at least assist them in obtaining some of that knowledge which would materially aid them in their art progress. In architecture especially, how difficult it seems to get that enviable desideratum, ‘ the scientific artist.” Sir Christopher Wren was a great example, perhaps; but where are we to look now-a-days for such a giant in art and science to reconcile for us these apparent extremes which are too often treated as distinct gifts or acquirements having little in common ? “ Art v, Science” is not the happiest heading to such a discussion. Are we to suppose it an impossibility for the artist to retain in their integrity the soul and feeling required in art, and yet to posses the higher powers of intellect which are so necessary in assisting him to give them expression ? Your correspondent ‘‘ W. R.” defines the difference pretty clearly, and has fairly replied to the question raised by “Art ;” but we must not speak of art in opposition to science, but rather as its indispensable adornment.—I am, &c., W. iH. L. —————EEE—— FOUNDATIONS FOR BUILDINGS. Srr,—I can quite corroborate Mr. Elborne’s statement in regard to the damage to buildings by the swelling and shrinkage of clay. I have perceived a much greater difference during the last five or six years than previously. I have also found houses that were formerly dry have during that period become very damp. I am inclined to think that deep subsoil drainage is the remedy required, I have tried it on a small scale with good effects, and expect this spring to apply it to a considerable extent. It is very probable that the excessively dry and hot summers that we have experienced lately may have opened extensive fissures in the clay, ad- mitting a great amount of moisture in a little time, without any means of passing away, except by evaporation during hot weather ; these fissures would not permanently close, but gradually become larger, and so the evil increases every year- I have particularly noticed the effect upon doors on several buildings. At one time they will be jammed so tight as to be difficult to open, at another time the difficulty will be to keep them closed, not from swelling but from alteration in the form of the door- frame from upheaving or sinkage of the ground. I hope to hear more on this subject from some of your numerous correspondents.—I am, Gc: S. I. B. eee MORTAR AND CONCRETE. Srr,—In a letter I wrote last week on concrete, I fear Iso worded it in one place as to lead a person to think that I absolutely recommended the materials of the pudding stone, whereas I only mean arrangement, leaving the materials of the concrete out of the question. In speaking of the quantity of lime to be used, I took it for granted that the lime was the purest of its kind—if not so, modifications will be required. It is well known that various limes require various quantities of sand; indeed, I have met with a lime which would not set if sand was put in at all. It is therefore clear that in the latter case no sand must be in the materials at all, and in the others sand must be diminished in proportion to the nature of the lime, and in all cases lime snbstituted for the sand. But there neyer was a rule without exceptions, if the above may be called such, since in reality there will be in the end only the same quantity of pure lime. As I have noticed the powers of various limes to take sand, pechaps it would not be amiss to notice once for all the various sands for requiring lime. I look upon mortar simply as a concrete with very small materials, to which I apply the same rule as I gave in my last, i.e, the lime must form an envelope round every particle. If ic do, the lime will be good, almost in spite of sand, providing too much lime be not in, In the latter case it cracks more in the set- ting, does not, I think, set so well, and, which is of more importance, absorbs more water. The power of lime (rich lime, of which 1 only now speak) to absorb water is well known. The grains of various sands are of various sizes, some very small and some comparatively large, and some (the best sand, by the way, all else being equal), of a mixed grain. It must be clear that the sum of the surfaces, for equal quantities of very fine sand, must be more than a larger grain, so that more lime is required to cover. The benefit of mixed-grained is that it forms a more perfect concrete, the small grains filling in the in- terstices between the larger. I have known small- grained sand cast aside when the addition of more lime would have made better mortar than the sand substituted. When very fine sand is used, with perhaps not more than half lime, after a time more or less extended, according to deficiency of lime, the lime appears to rot away, and Ihave heard it stated very gravely that the sand destroyed the lime and caused the mortar to rot. Whereas it never was mortar, but half sand, and sand, we know, will not stand the weather, but crumble away However, I suppose this will go on so long as we have the usual specification of three or two, as the case may be, to one given, and not left for the mortar to be made to suit materials, as to quality of both lime and sand. There are cases, however, where it looks very like rotting, but on examination a little more lime would have prevented it mostly; inothers the sand appears to be mixed with foreign matter, which may be more or less deleterious. To rot the lime would require chemical action, and nothing appears like ite lhe: use of sand in lime is purely mechanical ; it divides the lime into thin films, and puts it in position to arrange itself for acqueous crystallisation and for absorbing carbonic acid gas. Very fine grained is to be avoided, simply from the great quantity of lime it requires, and it makes the mortar too nearly to resemble solid lime far after chemical changes. Mortar, I think, ought all to be chopped up with spade to toughen it and to work the sand and lime together better. Upwards of forty years ago, when I went first to the trade, all was done so, or spade- mixed and wrought. Those rakes for mixing mortar were never seen, not being required. I hate the sight of a mixing-rake myself yet for finishing mixing, but perhaps this partly proceeds from early training. Besides, the rake will be used to finish mixing, and mortar used unspade-wrought, in spite of all I may say; and I probably only hate it with mortar because I insist on it both for concrete and béton. I, of course, know that the rake is indis- pensable as mortar is now made. I must not proceed with concrete making, or it may be thought that my work is to be all preface; yet I must notice the states in which lime may be used. These are ground, slaked, and made into mortar. Nothing but ground lime ought to be used for concrete, but it ought to be well groun4, not, as is generally done in London, with non-hydraulic lime, which contains fully one-fourth or more of uncrushed lumps from the size of a small marble downwards. These lumps do not slake to get mixed thoroughly with sand and gravel. They swell afterwards, form- ing disintegrating points, and centres for attracting damp. I saw some of the concrete made with it many years before, and it was not as hard as ours was in a day or two, I take it the grate-bottomed pugmill it is pretended to be ground in must have been invented by a mechanical genius from Colney Hatch, or some such place. Chalk lime ought ever, if possible, to be avoided being used, for in large masses the centre will net set. One of the bastions of the fortifications of Strasburg, put up by Vauban, was taken down more than 150 years after, and the chalk mortar used was found in about the same state it was putin. Slaked lime, if hydraulic and ener- getic, may be used for concrete very well if time can be allowed to set, but never so use non-hydraulic. However, I should prefer it made into mortar and the materials made béten of.—I am, &e., G. A. Weppie, An Old Clerk of Works. 37, Hyde-street, Winchester, Dec. 22, 1871. DAN see HOT-WATER PIPES AND FIRES. Srr,—Like your correspondent “ T. L.,” I cannot understand how any ordinary use of hot-water pipes should interfere with the fire insurance of a house. In my opinion, and generally speaking, there is ten times more danger of fire from the gas-burning in a house than from its hot-water pipes. Supposing the hot-water pipes were of lead, I should expect to see them melted by the hot water as soon as I would expect to see hot-water pipes setting wood on fire, especially at a distance of “ 60ft. away from the kitchen boiler.” I should like to hear a sensible ex- planation from the fire insurance office of its reasons for refusing the insurance.—I am, &c., ee
 * 31, TAVISTOCK-STREET, COVENT-GARDEN, W.C.