To become familiar with different kinds and qualities of timber requires considerable practice and close observation. Pine should have a fine close grain, the annual rings should seldom exceed one-tenth of an inch in thickness, and be firmly connected together. The nearer the concentric layers are to circles and ellipses, the less likely is the timber to be defective, as sudden swells are frequently caused by "rind-galls," which are wounds in a layer of the wood that has been covered over by the growth of subsequent layers.

Superior pine timber is also strongly charged with resin, which not only gives it strength and elasticity, but also preserves it from insects and prevents fermentation and decay. The colour of good timber should be of a clear or bright yellow, with a reddish cast alternately. The wood should appear hard and dry to the touch. The smell should be strongly resinous, especially when the timber is exposed to the sun or heat, or when the shavings are rubbed between the fingers. It should neither leave a woolly surface after the saw, nor fill its teeth with resin. On the contrary, when the layers are separate, porous, or open, with tints of a pale red near the heart, and white spots intermixed, or of a dark red, with the resinous particles of a blackish colour, the timber is in a state of decay. Likewise, when pine is cut transversely, and the colour does not appear uniform, but interspersed with veins, and the smell is either entirely gone or has become fetid, the timber may be considered past its prime and approaching a state of decay. Mr. Fincham says, "The experienced mast-maker forms his opinion of the quality of a stick not only from the colour, smell, and appearance of the grain, but by its working; for as a stick is more or less frough or fragile, the greater or less difficulty he has in separating its parts as he chops them off. If the timber is good, its parts, on being separated, appear stringy, and oppose a strong adhesion; and the shavings from the plane will bear to be twisted two or three times round the fingers; whereas, if the stick is of a bad quality, or in a state of decay, and has lost its resinous substances, the chips and shavings come off short and brittle, and with much greater ease."

The inferior kinds of timber have thick annual rings; in some the dark parts of the rings are of a honey yellow; the wood is heavy and filled with soft resinous matter; it feels clammy and chokes the saw. Timber of this kind is not durable, nor fit to resist heavy loads or strains.

The timber grown in Mar Forest is often of this latter kind. In other specimens of inferior timber the wood is spongy, contains but little resinous matter, and presents a woolly surface after the saw. Swedish timber is often of this kind, and is then inferior in strength and stiffness.

The mean strength, stiffness, and toughness of oak being each represented by 100, those of the different varieties of Northern pine will be represented by the following numbers: -

The author was favoured by Mr. John White with a specimen of Norway pine much superior to any of the pine species that had been experimented upon; its strength being to that of oak as 120 to 100, and its weight per cubic foot 39 lbs.

The wood of the Pinus sylvestris from cold climates appears to be always much harder than that grown in warmer countries. It is from the under-side of crooked pine-trees that the Laplanders procure what they term "kior," which is as hard as boxwood, and which they use for the bottom of their sledges and for the outer part of their bows. The Norway timber is also harder than that from Riga or other warmer latitudes.