1841.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



207 



which I made on the St. Lawrence, counted upwards of thirty men 

 working the steering oars of the large rafts on tliat river, from which 

 some idea may be formed of the number of their inhabitants. Those 

 rafts are brought down the American rivers from distances varying 

 from one hundred to twelve hundred miles, and si-x months are often 

 occupied in making the passage. When it is at ,nll possible, they 

 moor them during the night in the still water at the edge of the river, 

 but when this camiot be done, they continue their perilous voyage in 

 the dark, exhibiting lights at each corner of the raft to warn^vessels 

 of their approaclvtovthem. The St. Lawrence rafts vary from 40,1100 

 to-300,00U square'feet, or from about one to no less than seven acres 

 in -surface, «nd some of them- contain as much as £5000wortb of tim- 

 ber, df not marKiged with great skill, these unwieldy specimens of 

 naval architecture are apt to go to pieces in descending the rapids, 

 and it not unfrequently happens- that the labour of one, and sometimes 

 two seasons is in this way lost in a moment. An old and experienced 

 raftsman, with whomi had some conversation on board of one of the 

 St. Lawrence steamers, informed me that he, on one occasion, lost 

 ^•250U by one raft which grounded in descending a rapid and broke 

 np. He said the safest size for a raft was from 40,000 to 60,000 

 square feet, or about one acre, and that five men were required to 

 work a raft of that size. 



The species of forest trees indigenous to different countries is an 

 inferesting subject connected with vegetable physiology. There are 

 said to be about thirty forest trees indigenous to Great Britain, which 

 attain the height of thirty feet; and in France there are about the 

 same number. But according to the best authorities, there are no less 

 than 140 species which attain a similar height indigenous to the 

 United States. 



To notice each of these numerous species, whose timber is employed 

 by the Americans in the arts, even if I were able to do so, would 

 greatly exceed the limits to which I am. restricted by the nature of the 

 present communication, and I shall therefore only make a few remarks 

 regarding those timbers which are most highly prized and most ex- 

 tensively used in the ship carpentry and public works of the country. 

 The first which I shall notice is the Live Oak (Querciis vireiis), so 

 named because it is an evergreen, its leaves lasting during several 

 ye-ars and being partially renewed every spring-. It grows only in the 

 southern states, and is one of the most valuable of the American tim- 

 bers. The duty imposed by our government on wood from the 

 United -States, prevents its importation into Britain, and as live oak 

 grows only in the United States and is not found in Canada, it conse- 

 quently never reaches this country as an article of commerce ; the 

 whole produce being consumed by the Americans themselves in ship- 

 building. Its specific gravity is equal to, and in some cases greater 

 than, that of water, and it is used along with white oak and cedar for 

 the principal timbers of vessels. The climate, according to an Ame- 

 rican authority,* becomes mild enough for its growth near Norfolk in 

 Virginia, though at that place it is less multiplied and less vigorous 

 than in more southerly latitudes. From Norfolk it spreads alon^ the 

 coast for a distance of loUO or ISOO miles, extending beyond the 

 mouths of the Mississippi. The sea air seems essential to its exist- 

 ence, for it is rarely found in the forests upon the mainland, and never 

 more than fifteen or twenty miles from the shore. It is most abundant, 

 most fully developed, and of the best quality, about the bays and 

 creeks and on the numerous fertile islands which lie scattered for 

 several hundred miles along the co-ast. The live oak is generally 

 forty or fifty feet in height, and from one to two feet in diameter, but 

 it is sometimes much larger, and its trunk is often undivided for eigh- 

 teen or twenty feet. There can be little doubt, from its great density 

 and durability, that this is one of the finest species of oak that exists, 

 surpassing even that for wdiich Great Britain is so famous. Its culti- 

 vation has been tried in this country without success ; but could it be 

 imported, it would be found admirably suited for the construction of 

 lock-gates and other engineering works, for which hard and durable 

 timber is required, and for which English or African oak is generally 

 used. 



The White Oak (Qiiercus alba) is the sp£cies of which so much is 

 imported into this country. It is known by the name of "American 

 oak," but it is a very different and much inferior wood to the live oak 

 of the United States which I have just described. It is also much 

 more widely distributed, and occurs in much greater quantity, than the 

 live oak. It is very common throughout the northern states and in 

 Canada, from whence it is exported to this country. It attains an 

 elevation of seventy or eighty feet, with a diameter of six or seven 

 feet. It is known by the whiteness of its bark, from which it derives 

 its name, and from a few of its leaves remaining on the branches in a 

 withered state throughout the winter. The wood is of a reddish 



* The Sylva Americana, by J. D. Browne. Boston, 1832. 



colour, and in that resi>ect is very similar to English oak. But it is 

 generally acknowledged to be greatly inferior to it in strength and 

 durability. It is very straight in the fibre, however, and can be got 

 in pieces of great length and consider.iblejscaiitling — properties whichi 

 for certain purposes, make it pi-eferable to the British oak. It is much 

 used in ship-building, and also for the transverse sleepers of railways. 

 There aremany other oaks in the United-States, but the two I have 

 mentioned are those most in use. 



The pines are perhaps the. nest woods in importance to the oaks. 

 The species of those are -also very numerous, and I shall only mention 

 one or' two of theanost- important of them. 



The White, ^)r Weymouth Pine (Pinus sirobus),:is widely distri- 

 bute'd both in the United States and in 'Canada, and is exported to 

 Britain in great quantities from the latter country. It is tlie tallest 

 tree of the American forest, having been known, according to Michaux, 

 to attain the height of 180 feet. The wood has not much strength, 

 but it is free-from knots, -and is easily wrought. It is very extensively 

 employed in the erection of bridges, particularly frame and lattice 

 bridges, a construction peculiar to the United States, and very gene- 

 rally adopted in that country, which I have described in detail else- 

 Vfhere.* For this purpose it is well fitted, on account of its lightness 

 and rigidity, and also because it is found to be less apt to ii^ai-p or cast 

 on exposure to the atmosphere than most other timbers of the country. 

 It is much used for the interior fittings of houses, and for the masts 

 and spars of vessels. 



The Yellow Pine (Pinus milis or mriabilis) occurs only in the 

 southern and middle states, and is not found in Canada, and therefore 

 does not reach this country, the wood known by that name in Britain 

 being the Pnnis resmoaa. ' It attains the height of 50 or bO feet, with 

 a diameter of i! or 3 feet, and is the timber which the Americans em- 

 ploy in greatest quantity for the masts, yards, booms, and bowsprits 

 of their vessels. A large quantity of it is annually consumed for this 

 purpose in the building-yards of New York, Philadelphia, and Bal- 

 timore. 



The Red Pine (Pinus resiiiosa) is the only other of the pine species 

 that is much used. It occurs in great plenty in the northern and 

 middle states, and in Canada, from whence it is e-xported in great 

 quantity to this country, and it is known to us by the name of "Ame- 

 rican yellow pine." It attains the height of 70 to 80 feet, with a 

 diameter of two feet, and is remarkable for the uniform size of its 

 trunk for' two-thirds of its height. Its name is derived from the red- 

 ness of its bark. The wood, owing to the resinous matter it contains, 

 is he-avy ; and is highly esteemed for naval architecture, more espe- 

 cially for decks of vessels, both in this country and in America. 



The Locust (Robinia psend-acacia), from the beauty of its foliage 

 and the excellent qualities of its timber, is justly held in great esteem 

 in America. It abounds in the middle states, and in some situ-ations 

 attains the height of seventy feet, with a diameter of four feet. The 

 wood of the locust tree is of a greenish yellow colour, marked with 

 brown veins, not imlike the laburnum of this country. It is a close- 

 grained, hard, and compact wood, and is of great strength. It is 

 used, along with live oak and cedar, for the upper timbers of vessels, 

 and is almost invariably used for treenails, to which it is weU adapted. 

 It is also employed in some parts of the country as transverse 

 sleepers for railways: Its growth being chiefly confined to the 

 United States, it is not imported into Britain, It is one of the very 

 few trees that are planted by the Americans, and may be seen forming 

 hedge. rows in the highly cultivated parts of Pennsylvania. 



The Red Cedar (Jujiiperua Vtrginiana) is another valuable wood, 

 the growth of which is confined to the United States. In situations 

 where the soil is favourable it grows to the height of 40 or 50 feet, 

 with a diameter of 12 or 13 inches. This wood is of a bright red 

 colour; it is odorous, compact, fine-grained, and very light, and is 

 used, as already stated, in ship-building, along with live oak and 

 locust to compensate for their weight. It is considered one of the 

 most durable woods of the United States, and being less affected by 

 heat or moisture than almost any other, it is much employed for rail- 

 way sleepers.- I remember, in travelling on some of the railways, to 

 have been most pleasantly regaled for miles together, with the aroma 

 of the newly laid sleepers of this wood. It is now, however, becoming 

 too scarce and valuable to be nsed for this purpose. 



The White Cedar (Oupressus t/njoides) and the Arbor Vita (T/mja 

 occidaitalis) are employed for sleepers and other purposes to which 

 the red cedar is applied, but the latter is preferred when it can be 

 obtained. 



The onlv other tree -svhich I shall notice is the Sugar Maple (^cer 

 satcharinum) which occurs in great abundance in Canada and the 



* Stevenson's Sketch of the Civil Engineering of North America. Lon- 

 don: John Weale, 1S38. 



2 2 



