March i, 1886.] .THE TROPICAL AGRICULTURIST. 



627 



tbo soil is pressed about tile roots tlie more saud or 

 its equivalent should be mixed with the soil. For 

 the production of flowers firm potting is an important 

 factor ; for foliage and quick growth loose potting 

 is best. 



lu conclusion, a word of warning may be uttered 

 agaiust filling the pots too full of soil, so that in- 

 sufficient room is left for watering. The more soil 

 a pot contains the more water will be required to 

 thoroughly moisten it when dry. This seems plain 

 enough, but, as was said by oue of those who took 

 part in the discussion above referred to. " AH these 

 simple matters are plain enough, but many gardeners 

 fail to see the importance of observing them. We 

 all know how to jjot a plant perhaps, but we do 

 not all pot it properly." — 'W. N. — Joiimal ./' Horii- 

 enltire. 



WOOD. 



KY JOHN WOODLAND, F. L. S., &C. 



{Read before the Chemi-^ts' As.sistant.-i' As^tociation.) 



AVood is a hard, permanent, cellular, and vascular 

 structure formed by plants, liy them it is used, in 

 a younger state, for mechanical support and to convey 

 fluids; in an oUler conditiou, still as a support, anil 

 to contain secretions peculiar to the plauts. The 

 following woods are useil when elasticity is required: 

 ash. hazel, hickory, lancewood, and yew. 



The following are in use when toughness is required, 

 combined with elasticity: beech, elm, hornbeam, oak, 

 and walnut. 



For durability in dry situations, cedar, chestnut, 

 oak, poplar, and yellow pine are chosen. 



For colouring purposes, Brazil wood, camwood, log- 

 wood, and Nicaragua wood are used to furnish a red, 

 green ebony a green, and fustic a yellow colour. 



For shipbuilding, elm, fir, larch, pine, and teak are 

 u.scd. 



For piles, as supports for piers or landing-stages, 

 &c . alder, beech, elm, oak, and plane are in common use. 



For housebuilding purposes, the ash, chestnut, fir, 

 oak, pine, and sycamore are much used. 



Where hard woods are required, box, lignum vit;e, 

 and mahogany are servicable. 



Timber is wood which has been prepared from trees 

 or shrubs, so as to be fit and durable for the pur- 

 pose for which it is selected. When soft or moder- 

 ately soft wooded trees are to be felled, raid-winter 

 is the best period of the year, on account of their 

 containing the lea.st amount of sap at that time; the 

 next best period being the middle of summer, as, al- 

 though at this latter period there is a large quantity 

 of fluid in the stem, still there is not the same 

 amount of nitrogenous fermeutAble principles as are 

 found in spring and autumn. If the tree be a hard- 

 wood one the period of the year at whiih it is felled 

 does not matter to any great extent. In order to 

 render the wood fit for timber it must be thoroughly 

 seasoned by slow drying. In this process the sap is 

 as well as possible evaporated, so that fermentation 

 and decomposition are avoided, and the wood is shrunk 

 to its furthe.st limit; the time usually required for 

 this to be accomplished is from two to three years. If 

 the wood is to be u.sed in an exposed position the 

 moisture with which it naturally comes into contact 

 would be liable with the constituents of the sap to cause 

 decomposition, hence water-seasoning is frequently 

 resorted to. A running stream being chosen, the logs 

 of wood are sank in it for about two or three weeks, 

 after which they are taken out and seasoned by slow 

 drying; in this latter process all the con.stituents of 

 the saji are washed away, and fermentation or de- 

 composition is thus prevented. Other means employed 

 to preserve wood which is exposed to moisture from 

 the soil, such as gati -posts, telegraph-poles, hope-poles, 

 and railway-sleepers, are (1) charring the outer sur- 

 face, V>y which the carlion set free, together with 

 other products formed and remaining outside, help 

 to preserve the interior from decay. (2) Vainting, 

 using with the paint fine sand, pumice, or finely- 

 powdered glass which has been previously incoqrarated. I 



(3) Immersing and standing in bitumen, tar, or 

 creasote ; in either of which cases the wood is pene- 

 trated to the centre by the preservative material. 

 (i) The process termed " kyani.sing," which is now 

 obsolete, and consisted of impregnating the wood 

 with perchloride of mercury by means of a solution 

 of the salt. (5) A proces.'i called " Uurnettising," 

 which has proved so successful at Woolwich, and 

 consists of soaking wood in a solution of zinc 

 chloride made in the proportions of 1 lb. of the 

 chloride to 5 gallons of water. A splendid example 

 of the preservative action of salt on wood is seen in 

 the salt-mines of Poland and Himgary, the wooden 

 supports in which have existed for ages. 



M'ood, when exposed to a damp surface and not 

 well ventilated, is often attacked by fungi, commonly 

 called <lry-rot, merulius lachrymas, merulius vestator, 

 and polyporns destructor, kv., the mycelia of which 

 rapidly spread, till in time the hard wood is replaced 

 by a small powdery-looking sub,stance. As the fungus 

 only attacks wood when it is moist, the term " damp- 

 rot '' is obviously more correet. In spite of the sub- 

 stitution of iron for wood, as in making giders, in 

 buildings, articles of furniture, tools, tVc, the import- 

 ation up to IH8:i has steadily increased, the following 

 being the returns for the past three years, in loads 

 of 50 cubic feet each :— In 18S2, 6,320,8«3 loads • in 

 1S83 6,5it",427 loads; in 1884, 6,132,925 loads. 



I will now proceed to enumerate some ordinary 

 woods, together with their sources and what pecu- 

 liarities they may furnish, 



AIdfi\ obtained from Ahius. gtutinona^ Betulaeeie. — 

 This wood is especially adapted for withstanding the 

 action of water, hence is used in connection with 

 cog-wheels of millstones, pumps, drains, piles in water 

 or mud, h' els of wooden boots, &c. According to 

 Virgil the first boats that were constructed were made 

 of this wood. The best gunpowder is also made from 

 the charcoal furnished by the alder. 



Asli, obtained from Fux'mus excelsior, Oleaceos. — This 

 wood is lighter in weight and more elastic than that 

 of the oak, and is less liable to be broken by a cross 

 strain, hence its use for billiard-cues, poles, ladders, 

 &c., but being fibrous it is more easily split than the 

 oak. The ash-tree when growing is regarded as being 

 a special attractor of lightning ; also the yule logs of 

 Christmas celebration were formerly furnished by this 

 tree. 



Axptii, from Populii.itremiila, Salicaceie. — The wood 

 is not so good as that furnished by the white poplar, 

 being porous, soft, and white ; it is chiefly used for 

 field-gates, milk-pails packing-cases, &c. 



Beech, from Fagiis si/lvatica, Oupulifer.-e. — The wood 

 is brittle and hard, but is apt to decay soon ; carpenters' 

 plane frames and other tool handlvs are made with 

 it, and cabinet-makers use it for shelves, kv. Next 

 to the oak this is the largest tree growing in England, 

 its height varying up to 100 feet, and at Hurnham 

 lieeches some splendid specimens can be seen. Of 

 this wood the Greek ship Argo was built, and in 

 ancient times the wine-bowls were made of it, and 

 hence the name of Bacchus, which we occasionally 

 see in connection with the wood. 



Jiirrh, from Betula nlha, Betulaee:e. — This is one of 

 the aboriginal trees of our island, as shown by the 

 presence of twigs still retaining their silvery bark 

 which are found in the lower strata of the peat bogs 

 existing in the North of Kugland ami around Manchester. 

 The wood known as Norway birch is much used in 

 the Highlands and further south for making wicker 

 hunlles, tying fagots of wood, and thatching straw- 

 roofs, its advantages lying in its toughness, pliability, 

 and durability. It is from the bark of this tree that 

 an oil is yielded from which the peculiar odour of 

 Kussia leather is derived. 



liriizil trood, obtained from Ctemilinnia ci-ista, 

 Leguminos.'e. — Tliis wood is used for dyenig purposes, 

 the colours obtained being red, rose colour, and yellow. 

 liratihlto irood is furnished by Ctenalptaia branUiensix, 

 and produces red and orange colours. 



Box, from Buxuh ^ewpervireitu, Kuphorbiaceie. — The 

 box-wood of commerce comes from Turkey, Asia Minor, 



