The diminution of the average rain, for the week of Full South declination, was therefore, in 1807, independent of, the dryness before attributed to the influence of the Full Moon in that year; which was a still more striking phenomenon. Let us see how the case stood, in this respect, in 1816.

Having divided the rain for this year also, according to the phases about, and between which it fell, and likewise computed the mean Temperature for each of the spaces (which are here denominated weeks) the results are as follow;

In 1816,

For the week about New Moon,

Rain 6 11 in. Temp. 47 10

For the week about First Quarter,

Rain 10 10 in. Temp. 46 60°

For the week about Full Moon,

Rain 9-13 in. Temp. 47 17

For the week about Last Quarter,

Rain 5.51 in. Temp. 48 39°
Mean 47 81°

Total 30 85 in.

For the week after New Moon,

Rain 5.21 in. Temp. 46.85°

For the week after First Quarter,

Rain 12.49 in. Temp. 46 88°

For the week after Full Moon,

Rain 741 in. Temp. 47.78°

For the week after Last Quarter,

Rain 4.20 in. Temp. 47.75′′
Mean 47.31°

Total 29 31

The Full Moon week in 1816, instead of being distinguished for dryness, as in 1807, was excessively wet the greatest depth of rain, however, fell in the space intervening between First quarter and Full Moon, and the driest part of the space included in each Lunar revolution was in the opposite part of the orbit, between the Last quarter and New Moon. The reader has only to turn over the Tables, from 114 to 126 inclusive, in the First volume, to be convinced of the fact in each instance.* With the exception of the week following the Summer solstice, in which there fell heavy rain before and after New Moon, the weight of the rain, this year, lies, in a very remarkable manner, within and about the third week of each period, or the space above mentioned; until we come to the latter part of the Eleventh Month and beginning of the Twelfth; when this space suddenly becomes dry, and that following the next Last Quarter becomes wet. It is observable, though I do not pretend to establish a connexion between the phenomena, that a Solar and a Lunar Eclipse are included in this period, which is so conspicuously dry in this very wet year, the rain being only half the average quantity of the season.

I have remarked that the Lunar orbit, in 1816, appears to have had a wet and a dry side, as it regarded the Moon's influence on the rain of our climate. It appears likewise from the preceding statement, that the Mean Temperature, taken about the phases, was highest for the Last quarter and lowest for the opposite part of the orbit, or First quarter, passing through a mean state for the intermediate phases, of New and Full Moon. Thus the cold aspect

* In Table 123, the marks Full M. and 1st Q. have been accidentally transposed,

of our attendant planet was, in this year, also the wet one; and the same arrangement that brought more warmth, brought also comparative dryness. And this, as in the very dry year of 1807, subject to a distinct and independent effect produced by the Moon's declination; to the consideration of which subject we may now return.

In order to place in a more striking light the effect of the Moon's declination on the Barometer, as well as to shew the agreements and differences in this respect, of a very dry and a very wet year, I have given, in Plate 6, four periods of 1807, and as many of 1816, taken in each case from the winter and spring; in which seasons these effects are the most conspicuous. These curves represent the movements of the Barometer from the day of the Moon's crossing the Equator, going South, to that of her return in the same direction to the same position. The regular curve, which accompanies them in each figure, represents the Moon's course in declination, the horizontal line being the Equator. In the upper figure, the curves are constructed from the medium height of the Barometer for each day, each of them having its mean point in the horizontal line. Consequently the reader, knowing the mean of the period, with the time of its beginning (both of which are given below), and availing himself of the help of an Ephemeris, for the successive times of the extreme South and North declination, &c. may verify for himself, by the Tables from 2 to 6 inclusive (vol. 1.), the accuracy of these delineations; the regular appearance of which, in some parts, may seem not unreasonably to require proof by measurement. Yet they are the result of observations, made without the remotest conception of their being ever applied to this standard, and in a

manner which I cannot but consider, now, as imperfect.

The lower, or second set of curves, give the variations of the Barometer at their full extent, as recorded on the face of the clock, of which I have already given an account in the Introduction to this work (vol. 1. xiii.), and in consequence of their shewing all the smaller variations, which are sunk and lost in the curves constructed from medium heights, their general appearance is very different from the former.

These curves will be found to agree nearly, but not exactly, with the observations in the Tables from 114 to 117 inclusive: the latter having been obtained not from the clock, but from a Barometer in the ordinary

way.

In the third or lowest figure, the four sets for each year are respectively reduced to a mean curve, which is adapted to a common mean line: and a medium curve, passing between these two, exhibits, finally, the total or average effect of the declination on the Barometer, for the whole of the space taken for this examination.

Time of beginning, and mean height of the Barometer, (represented by the horizontal line), for each of the curves in Plate 6.

For 1807,

Curve ab begins 30-31 of 12 Mo. 1806; mean line at 29.97 in.