SIU 
ferae. Essential character ; involncres mostly 
four-leaved ; fruit ovate, striated, 'lliere 
are seven species. 
SISYMBKIUM, in botany, water-cress, 
or water-rocket, a genus of the Tetradynamia 
Siliqnosa class and order. Natural order of 
SiliquosEB, Cruciforraes, or Cruciferae. Es- 
sential character ; silique opening, with 
straigbtish valves ; calyx and corolla spread- 
ing. There are fifty-three species. 
SISYRINCHIUM, in botany, a genus of 
the Monodelphia Triandria class and order. 
Natural order of Ensate. Irides, Jussieu. 
Essential character: spathe two-leaved; 
calyx none ; petals six, almost equal ; style 
one; capsule tliree-ceiled, inferipr. Tliere 
are ten species. 
SITE, or SciTE, denotes the situation of 
an house, messuage, &c, and sometimes the 
ground-plot, or spot of earth it stands on. 
In logic, situs is one of the predicaments 
declaring a subject to be so and so placed : 
and in geometry and algebra, it denote^ the 
isituation of lines, surfaces, &c. 
SITTA, the nut-hatch, in natural history, 
a genus of birds of the order Pic®. Generic 
character: bill straight; upper mandible a 
little longer; nostril small, and covered with 
bristles; tongue short, jagged, and horny 
at the tip ; four toes, the back one as large 
as the middle fore one. Latham notices 
seven species, and Gmelin twelve. The 
following is the principal: S. Europea, or 
the European nut hatch. This bird weighs 
about an ounce. Its manners much resem- 
ble those of the wood-pecker, in whose de- 
serted nests it often builds. When the fe- 
male is in a state of incubation, if she be at 
all annoyed by the touch of a stick, she will 
ntter a violent kind of serpentdike hiss. 
She is supplied with food, in ample abun- 
dance during her sitting, by the most active 
assiduity of her companion. The food of 
these birds consists of caterpillars, and all 
sorts of beetles and insects, as well as nuts, 
the last of which they are said to lioard ; 
and they crack them by the stroke of their 
bill with extreme dexterity. They run up 
and down trees in restless pursuit, like the 
wood-pecker. They are not migratory from 
England, but, like many other birds, change 
their haunts, from the open country, as win- 
ter approaches, to reside during the cold sea- 
son in gardens, orchards, and other warm 
inclosures. In a state of confinement they 
rarely perch like other birds'; and almost 
always slyep standing on the flooring of their 
cage. 
SIUM, in botany, water-parsn^, a gepus 
SKA 
of the Pentandria Digynia class and order. 
Natural order of Ur.ibellatae, or Umbelli- 
ferae. Essential character : involucre many- 
leaved ; petals cordate; fruit sub-ovate, 
striated. There are nineteen species. 
SIZE, is a sort of glue, used by painters, 
&c. The shreds and parings of leather, 
parchment, or vellum, being boiled in water 
and strained, make size. This substance i* 
used in many trades. Mr. Boyle mentions, 
among other uses, that fine red stands and 
hanging shelves are coloured wifli ground 
Vermillion tempered with size, and when 
dry are laid over with common varnish. 
There is also a size made of isinglass, in 
the same manner, and for the like pur- 
poses ; but this size will not keep above 
three or four days, so that no more should 
be made of it at once than present occasion 
requires. 
The manner of using size is to melt some 
of it over a gentle fire, and scraping as much 
whiting into it as may Only colour it, let 
them be well incorporated together ; after 
which you may whiten frames, &c. with it. 
After it dries, melt the size again, and put 
more whiting, and whiten the frames, &c. 
seven or eight times, letting it dry between 
each time : but before it is quite dry, be, 
tween each washing, you must smooth and 
wet it over with a clean brush pencil in fair 
water. 
SKAITE, ill ichthyology, the variegated 
raia, with the middle of the back smooth, 
and one row of spines on the tail. See 
Raia. 
SKATING, an exercise on ice, both 
graceful and healthy. Although the an-* 
cients were remarkable for their dexterity 
in most of the athletic sports, yet skating 
seems to have been unknown to them. It 
may therefore be considered as a modern 
invention, and probably it derived its origin, 
in Holland, where it was practised, not 
only as a graceftfl and elegant amusement, 
but as an expeditions mode’ of travelling 
when the lakes and canals were frozen up 
during winter. In Holland long journeys 
are made upon skates with ease and expe- 
dition; but in general less attention is there 
paid to graceful and elegant movements, 
than to the expedition and celerity of what 
is called journey skating. It is only in 
those countries where it is considered as an 
amusement, that its graceful attitudes and 
movements can be studied ; and there is no 
exercise whatever better^calculated to set 
off the human figure to advantage. The 
acquirement of most exercises may be at- 
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