will be found in all districts. The physical conformation of any given piece of country affects the rain-fall to such an extent as to make it impossible to apply to one district the results which have been found in another.

The gaugings in the Perthshire Highlands show this in a marked degree. The district is quite the opposite in physical features to the Gorbals. It is of the wildest and most rugged description, the mountain peaks shooting upwards, in many cases, from 1,500 to 3,000 feet above the valleys; the sides of the hills are rocky and precipitous; the valleys are very irregular in direction, sometimes running obliquely, and at others at right angles to each other. And the wind is swayed hither and thither as the mountains obstruct, or the glens induce, a passage. Of two gauges, each of which is at an elevation of 1,800 feet above the sea, the one at the head of the Duchray valley, the source of the river Forth, and on the eastern slope of Benlomond, shows upwards of a half more rain than the other, which is placed on the western slope of Benledi. This difference must be sought for from other causes than that of elevation.

The greater portion of the rain which falls on the west coast of Britain comes from the west and south-west; and it has been long established, that more rain falls upon the eastern slope of a range of hills than upon the western. It has been observed that the wind sweeps the rain-clouds with great velocity up the western slope, but when over the top they lose their momentum and deposit their rains. These two gauges, it must be observed, however, are not upon opposite sides of the same range of hills, for between the Benledi gauge and the one on Benlomond we have the Duchray valley, and the valleys of Loch Chon and Loch Katrine, with the mass of Benvenue between the latter.

The Bridge of Turk gauge may be said to be in a position similar to the Benledi gauge, and the results are much the same. The Glengyle gauge, though at an elevation of only 380 feet, shows as much rain as the Benlomond gauge, but it is in a precisely similar position: it is at the eastern base of Benhonie, which has comparatively open ground to the south-west, as far as the Cobbler. The gauge between Loch Ard and Loch Katrine has also a rising ground to the west; while at Aberfoyle, at an elevation of 60 feet above the sea, at the eastern end of a valley some miles in length, in which the clouds have had time to deposit their rain, the fall is the least in the district, being only one-half of what is got at the Benlomond and Glengyle gauges.

The result of the gaugings made on the Shaws Water district, near Greenock, also show the marked effect the configuration of the country has upon the amount of rain-fall. These gauges, of which there are five, have been kept by Mr. Morrison, the manager of the works, since 1835.

They are placed at elevations varying from 480 to 800 feet above the sea, and the average of the twenty-five years' gaugings is as follows:

Everton Gardens,
No. 4,

61.50 Inches.

56.75

Here the highest gauge gives the least rain, while the greatest is obtained at an elevation of 560 feet. I have not visited all these gauges myself; but I am informed by Mr. Morrison that the gauge which gives the greatest fall is at the base of a hill sloping towards the north-east. The Everton gauge is very much in the same position, while the others are more or less exposed to the west. The town of Greenock itself would, I have no doubt, from its position, give a large amount of rain-fall, but I have no gaugings to show.

In a hilly country the greatest care ought to be exercised by the engineer in placing his rain gauges, when it is sought to arrive at an average rain-fall over any given district. The more elevated and precipitous the hills are, the greater are the variations in fall at places comparatively near each other. I am of opinion that points of extreme fall in such districts can be assumed with much greater certainty than points of mean fall, and that the truest method of discovering the average, is to set about finding the extremes. In the beginning of this year I planted four additional gauges in the Loch Katrine district, and their results should help materially in arriving at a correct mean.

TABLE No. I.

RAIN-FALL AT THE GORBALS WATER WORKS,
FROM 1849 TO 1853 INCLUSIVE.

Average of the two Rain Gauges marked No. 1 and No. 2 in Table No. II. Average Height of Gauges 295 feet above the Sea.

TABLE No. II.

RAIN-FALL IN THE LOCH KATRINE AND GORBALS DISTRICTS.
FROM 1854 TO 1860 INCLUSIVE.

LOCH KATRINE DISTRICT.

GLAS-
GOW.

GORBALS DISTRICT.

Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation 270 feet. 1800 feet. 380 feet. 60 feet. 1500 feet. 1800 feet. 20 feet.

280 feet.

310 feet.

550 feet.

700 feet.

6.8

7.1

1854. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Jan.... 8.5 6.6 12.0

9.1

4.73

5.00

5.00

...

...

TABLE II.-continued.

Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation Elevation 270 feet. 1800 feet. 380 feet.

1500 feet. 1800 feet. 20 feet.

1857. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches. Inches.