268 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[August, 



northern states. It attains tbe heiglit of 50 or GO feet, and is from 

 12 to 18 inches in diameter. The wood of this tree is soft, and when 

 exposed to moisture it soon decays. It is very close-grained, and 

 when cut in certain directions is remarkably beautiful, its tibres, owing 

 to their peculiar arrangement, producing a surface variegated with 

 undulations and spots. It is also susceptible of a very high polish. 

 These qualities tend to render it a valuable acquisition to the list of 

 American woods for ornamental purposes, for which it is very gene- 

 rally employed, and is well known in this country by the name of 

 •'Bird's Eye Maple." The wood of the Red-flowering Maple {jlcer 

 rubrum) is also employed for ornamental purposes, and is generally 

 known by the name of "Curled Maple." The cabins of almost all 

 American-built vessels are lined with these woods, or with mahogany 

 inlaid with them, and tliev are also much used for making the tiner 

 parts of the furniture of houses. 



The property of the sugar maple, however, from which it derives 

 its name, is of perhaps more importance in a commercial point of 

 view than its use as timber. I allude to its property of distilling a 

 rich sap, from which sugar is largely manufactured throughout the 

 United States. From two to four pounds of sugar ccn be extracted 

 annually from each tree without hurting its growth. I had an oppor- 

 tunity of making some inquiries regarding this simple process when 

 on the banks of the river Ohio, where I saw it in progress. One or 

 two holes are bored with an augur, at the height of about two feet 

 from the ground, and into them wooden tubes, formed of the branch 

 of some soft-heaited tree hollowed out, are inserted. The sap oozing 

 from the maple flows through the tubes, and is collected in troughs. 

 It is then boiled until a syrup is formed of sufficient strength to be- 

 come solid on cooling, when it is run into moulds and is ready for use. 



Such is a brief notice of some of the principal timbers of the United 

 States, which, from their great abundance and variety, are suitable for 

 almost every purpose connected with the arts, and thus serve in some 

 degree to compensate for the want of stone, while at the same time 

 they afford great advantages for the prosecution of every branch of 

 carpentry, an art which has been brought to great perfection in that 

 country. Many ingenious constructions have been devised to render 

 timber applicable to all the purposes of civil architecture, and in no 

 branch of engineering is this more strikingly exemplified than in 

 bridge-building. Excepting a few small rubble arches of inconsider- 

 able span, there is not a stone bridge in the whole of the United States 

 or Canada. But many wooden bridges have been constructed. Seve- 

 ral of them, as is well knovvn, are upwards of a mile and a quarter in 

 length, and the celebrated Schuylkill Bridge at Philadelphia, which 

 was burnt about two years ago, but was in existence when I visited 

 the country, consisted of a single timber arch of no less than 320 feet 

 span. Canal locks and aqueducts, weirs, quays, breakwaters, and all 

 manner of engineering works have there been erected, iu which wood 

 is the material chiefly employed; so that if we characterize Scotland 

 as a stone and England as a brick country, we may, notwithstanding 

 its granite and marble, safely characterize the United States as a 

 country of timber. I shall only, iu conclusion, very briefly allude to 

 the appearance of the American forests, of which so much has been 

 written and said ; and on this subject I may remark, that it is quite 

 possible to travel a great distance without meeting with a single tree 

 of very large dimensions; but the traveller, I think, cannot fail very 

 soon to discover that the average size of the trees is far above what 

 is to be met with in this country. I measured many trees, varying 

 from 15 to 20 feet in circumference, and the largest which I had an 

 opportunity of actually measuring was a Button-wood tree (Plalanus 

 occidinlatis) on the banks of Lake Erie, which I found to be 21 feet 

 in circumference. I saw many trees, however, in travelling through 

 the American forests, which evidently far exceeded that size, and 

 which my situation, as a passenger in a public conveyance, prevented 

 me from measuring. 



M. Michaux, who has written on the forest trees of America, in 

 speaking of their great size, states, that on a small island in the Ohio, 

 fifteen miles above the river Muskingum, there was a button-wood 

 tree, which, at five feet from the ground, measured 40 ft. 4 in. in cir- 

 cumference. Ht mentions having met with a tree of the same species 

 on the right bank of the Ohio, thirty-six miles above Marietta, whose 

 base was swollen in an extraordinary manner ; at four feet from the 

 ground it measured 47 feet in circumference, giving a diameter of no 

 less than 15 feet 8 inches ; and another of nearly as great dimensions 

 is mentioned by him as existing in Genessee ; but these trees had per- 

 haps been swollen to this enormous size from the effects of some dis- 

 ease. He also measured two trunks of white or Weymouth pine, on 

 the river Kennebec, in a healthy state, one of which was 154 feet long 

 and 64 inches iu diameter, and the other was 142 feet long, and 44 

 inches in diameter, at three feet from the ground. M. Michaux also 

 measured a white pine which was C feet in diameter, and had reached 



probably the greatest height attained by tlie species, its top being 

 ISO feel from tlie ground. It is difficult for an inhabitant of our islancT, 

 without having seen the American forests, to credit the statements 

 which have been made by various authors, as to the existence of these 

 gigantic trees of 180 feet in height (being about 4u feet higlier than 

 Melville's monument in St. Andrew Square, in Edinburgh) ; but such 

 trees undoubtedly do exist. Mr. James Macnab of the Koval Botanic 

 Garden, in a paper on the local distribution of different species of 

 trees in the native forests of America,* mentions having measured 

 numerous specimens of the Piiiiis slrobus in Canada, which averaged 

 16 feet in circumference, and 1 GO feet in height; and one specimen 

 which had been blown down, and of which the top had been broken 

 off, measured 88 feet in length, and even at this height was IS inches 

 in diameter. 



The ascent of the sap in trees is a subject which has long occupied 

 the attention of physiologists. Some difference of opinion, however, 

 exists regarding it, and hitherto it is believed no very definite con- 

 clusions have been arrived at ; — and although not strictly connected 

 with the subject of this paper, I may be excused for remarking, that 

 tlie quantity of sap required to sustain such enormous trees as these 

 I have been describing, and the source and nature of the power by 

 which a supply of fluid is raised and kept up, at the great height of 

 180 feet from tbe ground, are inquiries which, could they be satis- 

 factorily solved, would form most interesting and instructive additions 

 to our knowledge regarding vegetable physiology. 



Edinburgh, Ftbruary, 1841. 



ON' THE SYSTEM OF WARMING BUILDINGS BY HOT WATER. 



A Re]>hj to Mr. Perkins's " Answer" fin the Journal for June last, p. 201, J 

 to the Report presented to the Manchester Assurance Company. By John 

 Davies, and George Vardon Ryder. 



Mr. Perkins declaims against our " unfair report ;" and charges us with 

 "errors and misstatements," with " manifest absurdity," with "unjust and 

 absurd experiments," " conducted with any new rather than that of candid 

 investigation." Such charges are easily made on either side of a discussion, 

 and are most generally resorted to by those who are least warranted in ap- 

 plying them. We shall presently show how unmerited and irrelevant such 

 charges are in reference to us ; and we trust that we shall be enabled to 

 satisfy every disinterested reader, that Mr. Perkins has, in order to conceal 

 the weakness of his defence, indulged his feelings in this kind of phraseology, 

 which, from the facility with which he uses it, seems to be quite natural to 

 him. It usually happens, as in this case, that the use of such language leaves 

 every thing untainted but the reputation of him who utters it ; while it for- 

 feits every claim upon an opponent for any greater courtesy of expression in 

 reply thau the example would suggest, or the nature of the objections appear 

 calculated to excite. 



Our directions, as the reader of the preceding pamphlets will remember, 

 were "to inquire into the nature of the accidents jchich have recently oc- 

 curred from the use of the hot water apparatus ; and to institute a personal 

 investigation into some of the cases referred to ; and t j make such experi- 

 ments as might tend to satisfj' our minds as to the causes of the accidents 

 ichich had occurred" from the use of the apparatus as it has been erected in 

 Manchester, and not as it may have been since improved by the Patentee ; 

 for the latter being unknown until very " recently," that is to say, until our 

 Report had appeared, it was impossible for us to notice. 



We had to investigate the abuses, as well as the uses of the apparatus, as 

 hitherto jiut up in this town and neighbourhood ; for, if the abuses were 

 likely to be of frequent, or even occasional occurrence, if they could arise 

 from ordinary carelessness or mismanagement, it is clear that the danger to 

 property must be very considerable. Of the advantages of Mr. Perkins's " re- 

 cent" improvement we know nothing excepting what he tells us in his " An- 

 swer ;" but, how ill soever he may think of us, we do most sincerely assure 

 him, that if it really renders the apjiaratus secure, we shall hail its applica- 

 tion with much pleasure ; not altogether with a feeUng of satisfaction, re- 

 sulting from the consciousness that we have hastened, if not occasioned it, 

 by having proved that it was necessary. From his own shomng, therefore, 

 Mr. Perkins ought, in this case, to be grateful, rather than angr)-. We have 

 given to the ai)paratus a popularity which it did not previously possess, while 

 we have pointed out its defects; these defects Mr. Perkins affirms that he 

 has "recently" completely removed ; and, therefore, the very detection of 

 his former errors has tended to dittuse more widely a knowledge of his pre- 

 sent state of perfection. Had an "opportunity" been " afforded " to Mr. 

 Perkins " of assisting" us in our " experiments," it is far from probable that 

 he would ever have obtained these advantages, of the source of which he so 

 unreasonably complains. 



It seems to be almost impossible to satisfy Mr. Perkins. At first he con- 

 demns us because we attended to " appearances ;" and he afterwards inveighs 



• Agi-icultural Journal for 1835. 



