12S8
THEORY AND PRACTICE OF ENGINEERING.
Book II.
Olive. — This wood, when covered with mortar, endures a long time, and was muchemployed by the ancients to tic their walls together, as well as to form their roofs, whenthese were covered with stucco, and for all sorts of carpenters’ work.
Plane (Platanus orientalis) is a native of the Levant, and its wood much resembles thebeech ; the trunk of the tree grows very lofty and straight before it throws out branches.Pliny mentions one at Lycia the circumference of which was 81 feet; in its cavityeighteen persons were entertained at dinner. The wood is applied to many usefulpurposes by the joiner and cabinet-maker.
Plane ( Planus occidentalis) is produced in North America , and is of a more hardy qualitythan that just described: its diameter on the borders of the Ohio and Mississippi issometimes as much as 12 feet; it will last a considerable time under water, and is used forthe construction of quays, &c.; when dry it weighs from 40 to 46 lbs.
Poplar {Populus ). — The different kinds are useful in building; one is especially preferredin Lombardy, which, when cut into planks, has considerable durability ; Vitruvius says,where great strength is not required, At may be used, and certainly if maintained in adry state will last a long time : when applied for flooring boards, two or three years’seasoning is required, as it loses much of its bulk in drying ; it does not easily split bydriving nails into it, and it has an advantage over many other timbers in not catchingfire easily.
lbs. oz.
When green it weighs - - - - 58 3 per cube foot,
in dry state - - - - 38 7 —
Populus tremula, (trembling poplar,) is another variety,
weighing when green -
half dry -
quite dry -
lbs. oz.
54 6 per cube foot.40 8 —
34 1 —
Populus nigra , the black poplar ; its wood is more soft and fibrous, splitting with morefacility, and shrinking in its drying nearly one-sixth of its bulk; it is easy to work, doesnot splinter, and is useful to wheelwrights and turners.
lbs. oz.
In a green state it weighs - - - 60 9 per cube foot,
half dry - - - - - 42 13-
dry state - - - - - 29 0 —
Populus fastigiata (Lombardy Poplar ) is much used for the linings and fitting-up ofstore-rooms, as it is said mice will not attack it, and is well suited for the joiners’ workof a cottage : the weight of a cube foot in a dry state is 24 lbs.
Sycamore , or Great Maple : when in a dry state the wood is durable, but the worm soonattacks it; it is susceptible of a polish, and will not easily warp.
When green a cube foot weighs -half dry -dry -
Losing a twelfth part of its bulk in drying.
64 lbs.
56
48
Walnut (Juglans regia '). — The wood is solid, compact, easy to work, will neither warpnor crack, has a beautiful vein, and is rightly esteemed one of the choicest of English woods.Hilly and poor calcareous soils produce the finest timber ; when used in building it willbend under ordinary weights, but will not crack without giving due notice : rooms wains-coted with it have a good effect, and it was formerly much employed by cabinet-makers ;screws of presses and gun-stocks arc generally made of it.
lbs. oz.
When green it weighs - - - - 58 8 per cube foot,
dried - - - - - 46 8 —
Juglans alba grows to a large size ; its wood is very tough and flexible.
Juglans nigra has a more beautiful vein, and takes a higher polish, and is esteemed supe-rior to all other varieties for cabinet-work.
Willow ( Salix ) .• this wood is soft, smooth, and light, which occasioned it to be made intoshields by the Romans; if kept from wet, it will last a long time in rafters or other lighttimbers.
lbs. oz.
Salix caprea , a cube foot when dry weighs - 41 6
The first losing a twelfth, and the latter a sixth part of its bulk in drying.
In Scotland the red willow (S', fragilis) is used for building small vessels in conse-quence of its lightness, pliability, elasticity and toughness; the wood is of a salmon colour,