No More Learning

PAGE =32=, ll. 59-61. _To take a latitude, &c. _ The latitude of a spot
may always be found by measuring the distance from the zenith of a
star whose altitude, i. e. distance from the equator, is known. The
words 'At their brightest' are only used to point the antithesis with
the 'dark eclipses' used to measure longitude.

ll. 61-3. _but to conclude
Of longitudes, what other way have wee,
But to marke when, and where the dark eclipses bee_.

This method of estimating longitude was, it is said, first discovered
by noting that an eclipse which took place during the battle of Arbela
was observed at Alexandria an hour later. If the time at which an
instantaneous phenomenon such as an eclipse of the moon begins at
Greenwich (or whatever be the first meridian) is known, and the
time of its beginning at whatever place a ship is be then noted, the
difference gives the longitude. The eclipses of the moons in Saturn
have been used for the purpose. The method is not, however, a
practically useful one. Owing to the penumbra it is difficult to
observe the exact moment at which an eclipse of the moon begins.
In
certain positions of Saturn her satellites are not visible. Another
method used was to note the lunar distances of certain stars, but the
most common and practical method is by the use of well adjusted and
carefully corrected chronometers giving Greenwich time.

The comparison in the last five lines rests on a purely verbal basis.
'Longitude' means literally 'length', 'latitude', 'breadth'. Therefore
longitude is compared with the duration of love, 'how long this love
will be. ' There is no real appropriateness.


PAGE =33=. LOVES GROWTH.

ll. 7-8. _But if this medicine, &c. _ 'The quintessence then is a
certain matter extracted from all things which Nature has produced,
and from everything which has life corporeally in itself, a matter
most subtly purged of all impurities and mortality, and separated from
all the elements. From this it is evident that the quintessence is,
so to say, a nature, a force, a virtue, and a medicine, once shut
up within things but now free from any domicile and from all outward
incorporation. The same is also the colour, the life, the properties
of things. . .