230 SLATING. 
Day hide NSS tO ata ede 
Lime in state of carbonate, 
per cent, . da! 6 
Lime in state of silicate, 
7-19 0:26 1:98 0:25 0:22 .... 019 
0-24 062 0°30 1:09 0°43 0°50 ...- 
Total lime per cent., 743 088 2.28 134 0-65 050 0:19 
The proportion of lime, therefore, in the different 
beds of this formation issmall. In general, there- 
fore, the soils formed from them will be deficient 
in lime; and hence the reason why in practice it 
has been found that the addition of lime is an 
almost necessary preliminary to any successful 
and permanent improvement of the surface where 
these soils prevail. At the same time, it will be 
seen by the composition of No. 1 that some beds 
contain what may be called a large quantity of 
lime, and will therefore form soils that are of a 
richer character. The waters also that percolate 
through them, or the springs that rise from 
among them, will contain a considerable quan- 
tity of lime, and they may both sweeten the 
natural herbage, and when they collect in lakes 
and marshy places, may yield lime enough to ad- 
mit of the gradual deposition of beds of marl.— 
The old red sandstone slates also vary in the 
proportion of lime they contain. Such a slate 
from Fotheringham estate in Forfarshire gave— 
. 0°39 per cent. 
P 0°87 “ec 
Lime in the state of carbonate, 
Do. do. silicate, 
i Total lime, 1-09 per cent. 
The known fertility of certain soils belonging to 
the old red sandstone formation does not depend 
merely on the proportion of lime they contain; 
yet, in the less fertile parts of this formation, the 
per centage of lime contained in the rocks exer- 
cises a material influence on the agricultural 
capability of the soils which rest upon or are 
formed from them.” 
SLATING. In England where slates are very 
generally used for covering the best buildings, 
they are split and cut at the quarry into square 
plates, and are sold and distinguished by the 
following singular names, depending on their 
quality and size. 
Doubles, are : ‘ 1 ft. 2inches by 0 6 
Ladies, : , ; Ls pig: sts yO 8 
Countess’s, . A ; ee Oe Onl 
Duchess’s , ; Qiisweei tse) DY Lard, 
Queen’s (also called Rags), 3 ,, 3 ,, by2 3 
Inmnperialsiandypatents air i wuss tesla I Dyeai 2 
They are sold by the 100. The quantity neces- 
sary to cover a square of roofing of the first four 
kinds will weigh from 6 to 7 cwt. The large 
slates being also thicker will weigh from 7 cwt. 
toaton. The word patent applies to the mode 
of fixing and not to the slate. Slates, from their 
being thin and brittle, require a certain degree 
of skill in the cutting, making the nail holes, 
and laying, so as to prevent waste, and on this 
account their use is considered a separate branch 
of business, and is performed by the slater. Iron 
nails are used to fix shingles, and endure as long 
as the shingles will last ; but as good slates may 
be considered everlasting (unless broken or in- 
jured by accident), they ought to be. fixed with 
copper nails, that do not rust away. Roofs are 
SLEEP. 
occasionally covered with sheet lead, copper, or 
zinc, in all which cases they must be covered 
with planed boarding, and the long joints in the 
metal should be vertical, and not soldered, but 
so constructed as to admit of expansion and 
contraction. 
SLAUGHTERING. See Muar. 
SLEDGE. A slide-car or drag-cart. See the 
article Cart. An improved sledge, for carrying 
turf, hay, or other heavy commodities down slopes 
which are impracticable for any wheeled vehicle, 
may be made with iron-shod ash or elm soles, 
and ash rail body of 43 feet square or so at bot- 
tom, and drawn by chains of 7 feet in length, 
and bar-iron stilts of 5 feet in length, aided by 
a small friction wheel. A figure and plan and 
details of such a machine are given by Mr. 
Cook of Yetholm in the 8th volume of the 
Highland Society’s Transactions. 
SLENDER-BODIES. See Gromerters. 
SLINKING. See Axsorrion. 
SLEEP. The phenomena of sleep bear an 
immediate relation to the most general laws of 
Nature, and form an important illustration of 
the fact, that the periodical motions of the ani- 
mal economy are in direct correspondence with 
the movements of our planetary system, and 
especially with our situation relative to that 
sun which regulates the periods of the day and 
year. ‘All our wants reappear,” says Cabanis, 
“and all our functions execute themselves, in 
fixed and isochronous periods. The duration 
of the functions is the same in each period ; the 
same appetites or the same wants have the hours 
marked for their return ; and it commonly hap- 
pens, when these wants are not immediately 
satisfied, they diminish and disappear for a cer- 
tain time, only to return again with the greater 
force and importunity at the next succeeding 
period, which ought to produce a return of the 
impression. This character of periodicity is par- 
ticularly remarkable in the returns and duration 
of sleep, which commonly reappears during each 
astronomical day at the same hour; continues 
nearly for the same period of time ; and accord- 
ing as it is regular in its periods, slumber is the 
more easy, while the repose which follows is the 
more salutary and refreshing.” 
There are two principal states of vital activity, 
of which all animals partake in different degrees. 
When the vital excitement exists to its full ex- 
tent, the animal is said to be awake ; when the 
functions of life are suspended, either wholly or 
partially, it is said to be asleep. From this wak- 
ing state, when life exists in all its plenitude, 
there may be many degrees of its diminution, 
called reverie, delirium, dreaming, sleep, torpor, 
stupor, asphyxia, lethargy, according to their in- 
tensity, of which states the last is but one degree 
removed from absolute death. 
The principal occasions on which these states 
of vital repose naturally present themselves to 
our observation are, Ist, When the body and 
