642 
SEA 
SEC 
pending the thermometer exactly in the 
middle of it. "When it was used it was fast- 
ened to the deep sea-line, just above the 
lead, so that all the way as it descended the 
water had a free passage through it, by means 
of the halves which were then both open ; but 
the instant it began to be drawn up, both the j 
valves closed by the pressure of the water, 
and of course the thermometer was brought ; 
up in a body of water of the same tempera- i 
ture with that it was let down to.' With 
this instrument, which is much the same with 
one formerly described by Mr. Boyle, in his 
observations about the saltness of the sea, 
water was fetched up from different depths, 
and its temperature accurately noticed, in 
different seasons and latitudes. 
“■ August 27, 1772, south latitude 24°. 40'. 
The heat of the air was 72-§, — of the water 
attire surface 70, — of water from the depth of 
80 fathoms 68. 
“ December 27, 1772, south latitude 58°, 
2t'. The heat of the air was 31, — of the 
water at the surface 32, — of water from the 
depth of 160 fathoms 33\. 
“ In the voyage to the high northern lati- 
tudes before mentioned, they made use of a 
bottle to bring up water from the bottom, 
which is thus described : ‘ The bottle had a 
coating of wool, three inches thick, which 
was wrapped up in an oiled skin, and let into 
a leather purse, and the whole inclosed in a 
well-pitched canvas bag, firmly tied to the 
mouth of the bottle, so that not a drop of wa- 
ter could penetrate to its surface. A bit of 
lead shaped like a cone, with its base down- 
wards, and a cord fixed to its small end, was 
put into the bottle ; and a piece of valve lea- 
ther, with half a dozen slips of thin bladder, 
were strung on the cord, which, when 
pulled, effectually corked the bottle on the 
inside.’ We have here put down two of the 
experiments which were made during that 
voyage. 
“ August 4, 1773, north latitude 80\ 30'. 
The heat of the air was 32,— -of the water at 
the surface 36, — of water fetched up from 
the depth of 60 fathoms under the ice 39. 
September 4, 1773, north latitude 65°. 
The heat of the air was 66-'-, of the water at 
the surface 55, — of water from the depth of 
683 fathoms 40. 
“ It appears from all these experiments 
that, when the atmosphere was hotter than 
the surface of the sea, the superficial water 
was hotter than that at a great depth ; and 
when the atmosphere was colder than the 
surface of the sea, it is evident that the su- 
perficial water was somewhat colder than at 
a considerable distance below it.” 
Sea-water may be rendered iresh by freez- 
ing, which excludes or precipitates the saline 
particles ; or by distillation, which leaves the 
salt in a mass at the bottom of the vessel. 
Upon these principles, a mode of obtaining a 
supply of fresh water at sea was recommend- 
ed some years ago to the admiralty, by Dr. 
Irving. It consisted in only adapting a tin 
tube of suitable dimensions to the lid of the 
common ship’s kettle, and condensing the 
steam in a hogshead which served as a re- 
ceiver. By this mode a supply of twenty- 
live gallons of fresh water per hour might be 
obtained from the kettle of one of our ships 
ef war. 
The sea shall be open by the laws of 
England, to all merchants. The main sea 
SEB 
beneath the low-water mark, and round Eng- j 
land, is part of England, for there the admi- 
ralty has jurisdiction. 1 Inst. 260. 
SEAL, is either in wax, impressed with a 
device and attached to deeds, &c. or the in- 
strument with which the wax is impressed. 
Sealing of. a deed, is an essential part of it ; 
for if a writing is not sealed, it cannot be a 
deed. See Deed. 
SEALER, an officer in chancery, appoint- 
ed by the lord chancellor or keeper of the 
great seal, to. seal the writs and instruments 
there made in his presence, 
SEALING, in architecture, the fixing a 
piece of wood or iron in a wall with plaister, 
mortar, cement, lead, and other solid bind- 
ing. 
SEAMEN: by various statutes, sailorshav- 
ing served the king for a limited time, are 
free to use any trade or profession, in any 
town of the kingdom, except in Oxford or 
Cambridge. 
Rv 2 Geo. II. c. 36, made perpetual by 
2 Geo. III. c. 31, no master of any vessel 
shall carry to sea any seaman, his own ap- 
prentices excepted, without first entering 
into an agreement with such seaman for his 
wages: such agreement to be made in writing, 
and to declare what wages such seaman is to 
receive during the whole of the voyage, or 
for such time as shall be therein agreed upon ; 
.and such agreement shall also express the 
voyage for which such seaman was shipped 
to perform the same. 1 he provisions of this 
act are enforced by a penalty of ten pounds 
for each mariner carried to sea without such 
agreement, to be forfeited by the master to 
the use of Greenwich-hospital. This agree- 
ment is to be signed by eac-h mariner within 
three days after entering on board such ship, 
and is, when executed, binding on all parties. 
SEAM or Seme of corn, is a measure of 
eight bushels. 
Seam of glass, the quantity of 120 pound, 
, or 24 stones each five pounds weight. The 
seam of wood is a horse-load. 
Seams of a ship, are places where her 
planks meet and join together. There is 
also a kind of peculiar seam in the sowing of 
sails, which they call monk-seam ; the other 
seam of a sail is the round seam, so called 
from its being round like the common seams. 
SEARCHER, an officer of the customs, 
whose business is to search and examine all 
ships outward-bound, to see whether they 
have any prohibited or unaccustomed goods 
on board. 
SEASIN, or Seasing, in a ship, the name 
of a rope by which the boat rides by the 
ship’s side when in the harbour, &c. 
SEBATS. As the sebacic acid was, strict- 
ly speaking, unknown till the late experi- 
ments of Thenard, the description of the se- 
bats published by former chemists cannot be 
admitted as exact till they are verified by a 
new examination. These salts of course are 
unknown, if we except the few facts point- 
ed out by Thenard. This chemist, however, 
has announced his intention of publishing a 
detailed account of them. 
1. When sebacic acid is drop! into barytes 
water, lime water, or strontian water, it does 
not render these liquids turbid. Hence we 
learn, that the sebats of the alkaline earths 
are soluble in water. 
2. The alkaline sebats are likewise soluble. 
Sebat of potass has little taste, does not at- 
tract moisture from the air ; and when sul- 
phuric, nitric, or muriatic acid is poured 
upon it, sebacic acid is deposited. When 
the concentrated solution of this salt is mixed . 
with any of these acids, it becomes solid from 
the crystallization of the sebacic acid. 
SEBACIC acid. Chemists bad long sus- 
pected that an acid could be obtained from 
tallow, on account of the acrid nature of the 
fumes which it emits at a high temperature ; 
but it was M. Grutzmacher who first treated 
of it particularly in a dissertation He Ossium 
Medulla, published in 1748. Mr. Rhodes 
mentioned it in 1753 ; Segner published a 
dissertation on it in 1754 ; and Creil exam in- : 
ed its properties very fully in two dissert a- i 
tions published in the Philosophical Transac- 
tions for 1780 and 1782. It was called at 
first acid of fat, and afterwards sebacic acid. 
But at- the period when tlie.se chemists j 
made their experiments, the characteristic 
properties of the different acids were not suf- ‘ 
ticiently known to enable them to distinguish j 
acids from eacli other with precision, The- 
nard examined the subject in 1801, tried all 
the processes of Creil and Guyton Morveau, 
and found that the acids procured by them 
were either acetic, or the acid employed in 
the process. Real sebacic acid had hitherto- 
escaped the examination of chemists. It may 
be procured by the foliowing method, for 
which we are indebted to Thenard. 
L. Distil hog’s lard, wash the product with, 
hot water, separate this water, and drop into 
it acetat of lead. A flaky precipitate appears,.] 
which is to be washed and dried, mixed with 
sulphuric acid, and heated, A melted sub- ; 
stance analogous to fat, swims on the surface,] 
which is to be carefully separated. This 
substance is sebacic acid. It may be dis-| 
solved in hot water, and on cooling crystal- j 
line needles are deposited. This acid may 
be obtained also by evaporating the water 
employed in washing the product of distilled 
hog’s lard. Or this water may be saturated 
with potass, and afterwards precipitated with 
acetat of lead as above. Its properties are 
the following. 
2. It has no smell, its taste is slightly acid, j 
and it reddens the tincture of turnsole. When 
heated it melts like tallow. It is soluble in 
cold, but much more soluble in hot water. 
Boiling water saturated with it becomes solid 
on cooling ; alcohol also dissolves it abun- 
dantly. Ic crystallizes in needles; but by 
proper precautions it may be obtained in 
long, large, and very brilliant plates. 
It occasions a precipitate in the acetat and, 
nitratof lead, the nitrat of silver, the acetat 
and nitrat of mercury. It forms peculiar 
salts with the alkalies and earths. It does 
not render lime water, barytes, or strontian 
water turbid. Sebat of potass has little taste, 
does not attract moisture from the air ; and 
when sulphuric, nitric, or muriatic acid is 
poured upon it, sebacic acid is deposited : 
when its solution is concentrated and mixed 
with any one of these acids it becomes solid. 
SEC ALE, rye, a genus of the digynia 
order, in the triandria class of plants; and in 
the natural method ranking under the 4th 
order, gramina. The calyx is a glume of 
two leaves, which are opposite to one ano- 
ther, erect, linear, pointed, and les than the 
corolla. The corolla consists of two valves, 
the exterior of which ends in a beard. r l here 
4 
