144 
Sxqjptement to the " Tropical Agriculturist:' [Auglst 1, 189S 
this time the chick occupies I he smuUebt space in 
the egg, the iiir-hubhle takiug up about one-third 
of the egg-space. When the uir-bubble is broken, 
the chick commences its ,'^ti'uggies to hjave the shell, 
and in its efforts gnidually works itself up to top 
of thi egg till it lills t-he w iiolc spnce. This gives it 
move room, nud liberty to move nrouud, After 
the chick begins to use its lungs, it can be heard 
(if the egg is held close to the air) "pulling" and 
struggling for 8evernl minutes. The cliijiping of 
the shell is done by the beak, which has a small, 
hard, horny tip oil it. Owing to the position of 
the head and lie:ik, this horny tip comes in direct 
contact with the shell. The " chip " at the lirst is 
a small star-like fracture; after this the chick 
works itself round in the shell, at the same time 
cutting ofl the upper portion of the egg. After 
the chick escapes from the egg he re.sts for some 
time, to gain strength and prepare himself to be 
able to follow his parent. 
Chicks vary considerably in the time they take 
to free themselves from the egg. Much depends 
on the moisture in the egg, strength of chick, and 
thickness of tiie shell. Three to twelve hours is 
about the usual time taki^n. Just before the 
chick leaves the .-.hell it should have absorbed 
into the abdomen all the unused yolk, which i-t 
Its natural food for twenty-four or thirty hours. 
If chicks leave the shell before the whole of the 
yolk is properly absorbed, they will, in nine cases 
out of ten, die. 
Many things cause chicks to die in the shell. 
Some die from want of stamina or constitution, 
often hereditary or brought on by impure air. Of 
course some chicks die m the shell through over- 
exertion in trying to extricate them.-^elves from 
the egg. The chick, just belore leaving the shell, 
drawslts head from under its wing— where it had 
been folded— stretches out its neck, and rests 
after its labours, then a few more struggles, and it 
leaves the egg. 
The chick comes out of the egg covered with 
wet downy feathers; these featiiers possc^^s in- 
numerable minute branchlets, enclosed in delicate 
tubes. As the chick dries the tubes split, the 
branchlets open out and spread by their own 
elasticity, covering the little chick with its first 
coat of soft down: 
THE USES OP WOOD, 
{^Continued from page 108, Vol, IX.) 
14. Distillation of wood furnishes charcoal to 
the smithy or furnace, vinegar to the table, 
ftlcohol to the artisan, creosote to the wood 
preserver, gas for fuel and light, tar for root 
boards and pyroligneous oxalic, acetic, and other 
acids as well as acetone, paraffin, naphthalin, etc. 
to the manufacturing chemist, and, by a shght 
variation of the process, lampblack to the 
printer and painter. 
Wood also differs from the metals in several other 
respects. It is not fusible, it cannot be cast; 
hence to duplicate a form in wood requires the 
<,ame amount of effort as aid the original. Changed 
into pulp, and still more into cellulose, this draw- 
back is largely overcome. Wood cannot be welded, 
though, as stated before, this is more than com- 
^jensated by gluing; neverthleess, an end-to-end. 
junction of the kind produced in iron cannot 
b(! t'ffected. 
Wood cannot be rolled ; it must be cut into 
>hnjc' : but owing to its softness and clcavability 
thiv ivrpiires incomparably less t-ffort and 
eipiijiment than the rolling of metals. 
\\'ood i- hygroscopic: it contains water under 
all ordinary conditions, and tl'.e amount po con- 
tained v!irie.s with external conditions and with 
it the dimension of thb piece. Though an advan- 
tage in a barrel or tube, by nnikiiig it more 
secure ngoinst leakage, this peculiarity of wood 
is nevertheless a drawback not belonging to iho 
metals, but corresponding to the drawback in the 
use of metals occasioned by their annoying expan- 
sion and cttr.traclion due to change of temperature. 
Wood decays, iron and ,'=teel oxidize or rust. 
Both are serious drawbacks to the use of these 
materials, but since decoy depends on living or- 
ganisms, who=e multiplication is sometimes 
extremely rapid, at other limes olmost imper- 
ceptible, varying with the conditions of the 
wood (moisture, temperature, etc.)., the decay 
of woods is generally more damaging than the 
oxidation of metals. Under woter wood lasts 
longer than steel or iron. 
WlIKIIKIX THE WOODS KIFFKR. 
The properties which diiectly or indirectly 
lead the arti-an to prefer a particular kind of 
w ood fur u special purpo^e may be grouped into — 
(1.) Mechanical properties, such as etrengtb, 
toughness, stiffness, etc. 
(■J ) riiyticul, such as weight oud behaviour 
during and after teasuning. 
(i3.) Chemical, such as colour, durability, and 
value as fuel. 
(4.) Structural, such as texture, beauty of 
pattern, and length of fire. 
(5 ) Biological, such us size, form and abund- 
ance. 
MECHANICAL PROPERTIES. 
Of these several groups, the mechanical 
properties naturally take precedence, and of 
these again toughness and stiffn.ess are unques- 
tionably the most important, so that oven the 
most general classification of wnods into " Jiard 
woods " and " not hard woods '" (for this latter 
class, though by implication the conifers, has so 
far no name in this country) depends not at all 
on hardness as the word might suggest, but on 
toughness, the tough woods being the hard 
woods, the others the conifers. Since toughness 
is a combination of strength in .several directions, 
the various forms of strength should be first con- 
sidered separately. 
When in use, wood usually breaks in bending, 
as in the case of an axe or fork handle, or else in 
shearing or splitting as seen in planks and 
boards, whether on the sidewalk or in the wagon 
body. Wood fails much more rarely in com- 
pression, though much exposed to this form of 
strain, and still less frequently in tension, since 
in this direction its resistance is enormous, and 
can, in ordinary articles, never be brought to 
fair trial, 
Fundamentally, all strength of wood depends 
on four different forms of resistance, namely, 
the resistance to tension or lengthwise, separ- 
ation of the fibre, resistance to compression length- 
wise, resistance to compression sidewise, or to 
