LON 
tlie preservation of health and promoting 
long life, and the avoiding of excess, whe- 
ther in eating or drinking, is sufficiently obvi- 
ous. Some instances, indeed,are recorded of 
persons who have continued to commit ex- 
cesses, and have lived long ; but these are 
to be considered in no other light than as 
exceptions to a general rule ; and it may 
reasonably be contended, that if such per- 
sons lived to a great age, notwithstanding 
their intemperance, they would have lived 
much longer had they followed a different 
course. Experience will point out those 
articles of food which are best adapted to 
the constitution of each individual, and 
there cannot be a better rule than to ad- 
here to them as far as circumstances will 
permit. It may be observed, however, 
that people in general, especially those who 
do not labour, eat much more than nature 
requires ; that a little abstinence or self- 
denial may often be of use, either to pre- 
vent or to cure disease ; and at any rate, 
that none but hard working people, the 
young who are growing fast, or persons who 
are travelling about, should eat more than 
one full meal each day. 
As to clothingj much must depend on si- 
tuation and climate ; but it is generally 
found a useful practice to wear woollens 
next the skin. It is remarked in many 
parts of Scotland, that since the use of 
flannel shirts has been given up by the 
lower orders, the rheumatism and other 
diseases formerly unknown, have become 
very frequent, and are daily increasing. In 
the West India islands, if care be taken to 
make tlie troops w'ear flannel shirts, they 
are generallyexemptfrom various disorders, 
which otherwise would probably have at- 
tacked them. Even the negroes themselves 
are said to prefer flannel to cotton or linen, 
and find it a much more comfortable and 
useful dress. 
Exercise cannot be too much recom- 
mended ; and as the inhabitants of large 
towns, and persons engaged in sedentary 
occupations, cannot take all the exercise 
abroad that may be necessary for their 
health, they ought as much as possible to 
accustom themselves to be walking about 
even in their own house, for though this 
practice does not make up for the want of 
exercise abroad, it is certainly the best 
substitute for it. Exercise is attended with 
the advantage of creating an inclination to 
retire early to rest, and of inducing sound 
sleep. Every one should take all the re- 
pose that nature requires, but should never 
LON 
continue long in' bed witliout sleeping. 
Early rising, even ifcarrie.d to an extreme, is 
far more conducive to health and long life, 
than late hours at night and slumbering in 
bed in the morning. 
There is nothing that can tend more to 
long life than for a person to obtain a com- 
plete command of his passions, and in parti- 
cular to preserve liis mind from being 
ruffled by the occurrences of life. Perhaps 
there is no maxim more likely to promote 
good health, and consequently the duration 
of life, than that of paying a proper atten- 
tion to temper, temperance, and sleep. By 
good temper the mind is preserved from 
disease ; and by temperance, the body ; 
and both the mind and tire body, when ex- 
hausted, are again recruited and restored 
to their former strength, by a sufficient 
quantity of repose. 
LONGIBJETRY, the art of measuring 
lengths, both accessible, as roads, &c. and 
inaccessible, as arms of the sea, &c. See 
Surveying. 
LONGITUDE of a star, in astronomy, 
an arch of the ecliptic, intercepted between 
the beginning of Aries and the point of the 
ecliptic cut by the star’s circle of longitude. 
See Circle, &c. • 
Longitude of a place, in geography, is 
an arch of the equator intercepted between 
the first meridian, and the meridian pas- 
sing through the proposed place; which 
is always equal to the angle at the pole, 
formed by the first meridian and the me- 
ridian of the place. 
The first meridian may he placed at 
pleasure, passing through any place, as 
London, Paris, Teneriffe, &.c. hut among us 
it is generally fixed at London, or rather 
Greenwich, and the longitudes counted from 
it will be either east or west, according as 
they lie on the east or west side of that me- 
ridian. The difference of longitude between 
two places upon the earth is an arch of the 
equator comprehended between the tw'o 
meridians of these places ; and the greatest 
possible is 180 degrees, when the two places 
lie on opposite meridians. 
Since the parallels of latitude always de- 
crease, the nearer they approach the pole ; 
it is plain, a degree upon any of them must 
he less than a degree upon the equator, in 
the ratio of the co-sine of the latitude to 
the radius. Hence, as the radius is to the 
co-sine of any latitude ; so is the minutes of 
difference of longitude between two meri- 
dians, or their difference in miles upon the 
equator, to tlie distance of these two nierl- 
