266 THE YEAR-BOOK OF AGRICULTURE. 



Government, at Norfolk. The experiments were made under the direction of the Navy De- 

 partment, with a view of determining the proper time for cutting timber, and the best mode 

 of curing it or securing it from dry-rot. These are confined to the three principal kinds of 

 Bhip-timber, viz., live oak, white oak. and yellow pine, and will be of incalculable benefit to 

 the naval and mechanical interests of the United States. When we remember that there is 

 no table of specific gravity that is at all reliable for any meridian in North America, and that 

 our mechanics have been making their calculations from tables of specific gravity found in 

 European works, we shall begin to approximate a conception of its value. A location in the 

 timber districts of this wooded country for practical purposes will sati-ty the most incre- 

 dulous thai little is known about the productions of the American forest. 



The following is the order of the experiments followed by Mr. Jarvis: On the 13th of 

 September he received, in twelve-feet lengths, the butts of ten trees of live oak, and an 

 equal number of white oak and yellow pine; five of each kind were worked square at the 

 place where cut, and the remaining five were brought round with the bark on. After their 

 arrival, they were subdivided into three-feet lengths; the square pieces were from twelve to 

 fifteen inches square ; the round pieces in bark from twelve to fifteen inches in diameter. 

 The specific gravity of each piece was at once obtained, and then they were located as follows : 

 Four pieces of the squared live oak, and four pieces of the round live oak in bark, were placed 

 in tanks under cover, where were solutions of corrosive sublimate, alum, copperas, and coal tar, 

 and the same number of white oak and yellow pine, amounting in all to twenty-four pieces 

 of the varieties of ship-timber; one-half of which were square pieces, the other half round 

 and in bark. Those live oak, white oak, and yellow pine pieces were kept in the tank, sub- 

 merged one month, at the expiration of which time they were distributed as follows — under 

 cover in open air, planted as posts, and laid as railroad sills. There is a suitable number of 

 the pieces which have not been prepared, also under cover in open air. planted ns posts, and 

 laid as railroad sills. A proportion of the pieces aro square, and some round, and water- 

 soned for six months. After being removed from the water, two pieces are made of one, 

 and one kept under cover, the other in open air. The pieces which have not been in the 

 solution are the test-pieces; and among these pieces Mr. Jarvis has fitted some together, 

 wood and wood, except having between them tarred paper coated with oharooal-dust, A few 

 years will prove, by ocular demonstration, which of the solutions, substances, or water, will 

 make timber most durable. The pieces which have had no preparation on them, and arc 

 kont under cover, are weighed each month, to observe the amount of juices or moisture lost 

 by evaporation in one month and in one year. The object in weighing or obtaining the 

 specific gravity each month in the year is that he may be able to determine the best time for 

 cutting Bhip-timber, or whether it is of any material consequence; and, by testing the weight 

 Of tli" tame kinds of timber, in connection with its durability, thus set this matter at rest. 

 The timber u-ed for those experiments is thu- described: the live and white oak are of ex- 

 cellent quality, and foiled purposely, with a few exceptions, for these experiments. The 

 yellow pine is not as good u is used in the navy; its speoifla gravity will not prove the foot 

 The very best of yellow pine is not of the greatest density. Pitch-pine is not as good for 

 decks or deck-frames as other fine-grained pines from the South. The very best yellow pine 

 timl it in which the even fineness of the grain is continued to the centre or pith of 



the tree. P, y 08 1 ■e t ul obscrvat ion, much information that is valuable maybe obtained from 

 the table of s- j .<<i ti<- gravity: Qotwithstanding the thickness of the bark of the yellow pine, 



and its lightne-s, (the specific gravity differing DOt materially from thai of cork.) we timl 



that tin- pine timber in bark weighs much mors than the square timber. Tins, to ti asual 



rver, would hardly seem possible; the man unacquainted with the nature of yellow pine 



- tp -w i would be likely to doubt the c o rr ectn ess of the table. But such is the nature of 



the exterior coating immediately under the bark of yellow pine, that ws cannot find s more 



dogoui substance than that of sponge; its retentive prope r ti es similar, and the 



turpentine with which this sap-wood is saturated is the oauseofits increased specific gravity 



above that Of the squared timber, when covered with bark. The thinner the BSp-WOOd, the 

 the specific gravity. There is an error in the prevailing Opinion in relation to the dura- 

 bility of yellow pine timber. < htt government has become a heavy stockholder in this pre- 



