its power to hold vapour in an invisible state is being constantly augmented. Hence, not only is there no rain, but the clouds themselves are often seized upon by the dry air and dissolved. The soft south wind, on the contrary, comes loaded with the vapour which it sucked up when its temperature was comparatively high, and its capacity for carrying invisible moisture great. In travelling northwards it gradually cools, and the excess of moisture which it can no longer hold is condensed into clouds and rain.

Clouds are habitually less admired than they deserve to be. On fitting occasions cloud-gazing is no unworthy distraction wherewith to occupy a few of the fragments of time; and it belongs to those enjoyments which are all the more valuable because they so often lie within our reach. There is solid pleasure in letting our eyes lead fancy away among the mazes of cloud-land. What endless variety of form! The cirrhoid groups-how light, feathery, placid, gentle, and cheery! The bulky cumulus-stately, sombre, threatening! What is there grand in nature or in imagination which is not to be found in cloud-land? There are mountains and rocks, peaks and precipices, of which the aiguilles and domes of the Alps are but pigmy models, castles and cities, torrents and waterfalls! Imagination itself lags behind in its conceptions. Beautiful shapes float before our eyes for which we strive in vain to find a name. Under our gaze they melt, and change, and recombine, with the limitless fancy of nature. What colours!-the softest, the sternest, the richest, the brightest― hues of lead, copper, silver, and gold-all on a scale which mocks the rest of nature's painting. What masses and magnitudes!-mounds of vapour, built up out of specky fragments, and rolled up the vault of the firmament by the power of the sun. In repose clouds are the emblem

of majesty, but, driven before the gale, they are the symbol of force that is irresistible. "His strength is in the clouds!" When we see the vapoury masses glowing in the rays of the setting sun, we feel that the Psalmist, in calling them the "chariot of the Lord," chose for his metaphor the most gorgeous object to be found within the limits of the universe.

Thy mercy, O Lord, reacheth unto the Heavens, and Thy faithfulness unto the Clouds. Ps. xxxvi.

LIGHTNING AND CLOUDS.

O ye Lightnings and Clouds, bless ye the Lord: praise Him, and magnify Him for ever.

IKE other natural forces, lightning might with propriety have taken its place among the "Powers of the Lord;" but, from its having been, in conjunction with clouds, specially invoked by The Three Children in a separate verse, we are reminded of the great part it plays in warm climates, and of the beneficent office it performs. Lightning or Electricity exercises much influence in meteorological phenomena— in the condensation of clouds and rain, the production of currents and storms, and the aurora borealis—as well as in regard to the general sanitary condition of the atmosphere. Many of us know by experience how much our health and comfort are affected, even in this country, by the electrical state of the atmosphere; but we can form only a faint idea of the intensity of the inconvenience arising from it in hot climates. Hence, the thunder-storm, notwithstanding the danger occasionally attending it, is there welcomed as a blessing sent. to clear and purify the air, and restore it to its wonted salubrity.

Electricity, though it probably does not exist as a separate substance, but only as the expression of a pecu

liar mode of motion, is yet hypothetically and with convenience spoken of as a fluid. Its great reservoir is the earth, whose surface may be considered as a vast electrical apparatus on which the fluid is being constantly developed. When we desire by artificial means to exhibit the presence of electricity, we usually rub glass or sealing-wax with a silk handkerchief, or we cause a plate of glass to revolve rapidly and rub itself against a piece of silk, as in the common electrical machine. So, likewise, in the grand machine of nature, the air is constantly generating electricity as it sweeps or rubs over the earth's surface. A large proportion of atmospheric electricity.is likewise derived from the evaporation of water, which is constantly going on both from land and ocean; and in addition to this may be mentioned the electricity generated during the infinite variety of chymical actions everywhere at work over the globe. Now the fluid passing into the air from all these sources may accumulate unduly; and, the balance between the atmosphere and the earth being thus upset, nature steps in and takes means to restore the equilibrium. With this intent, copious rains streaming from the air sometimes draw off the excess to the great reservoir; but when the case is beyond this mode of relief, the firmament becomes loaded with thunder-clouds, from which dart the sparks that flash towards the earth. Or the disturbed electrical condition may exist only among neighbouring clouds, and the balance is then restored by the vivid passage of sheet-lightning from one to the other.

There are some substances such as metals and water that are called "good conductors," because electricity passes easily through them; and there are other substances such as glass or dry air-that are called "bad conductors," because electricity passes

through them with difficulty. In moving along the former, the fluid seems gentle and manageable; but in forcing a passage through the latter, it sometimes tears and destroys. Thus the wire which conducts into the earth the electricity from a machine may be held safely in the hand. The fluid will pursue its easy course through the wire to the ground, and will not turn aside to enter the hand and give a shock to the body by forcing its way through so bad a conductor. On this simple principle depends the utility of the lightningrod. In its flight towards the earth the lightning avoids a bad conductor, and selects a good one if it is to be had; hence it will spare the house or the tower so long as there is a sufficient iron rod attached through which it may descend to the earth. In this way the electric discharge, which would have shattered the "bad conducting" tower, glides easily and safely past it into the ground. Formerly people dreaded to enter a smith's forge during a thunder-storm; but now, being better informed, they wisely direct their steps towards it, well knowing that they cannot be in a safer position than when surrounded by masses of iron,—that is, with good conductors in contact with the ground.

As comparatively few places can be artificially protected by lightning-rods, Providence has made various natural arrangements to diminish the danger by which we should otherwise be surrounded during every thunderstorm. Thus it so happens that water, whether in the form of liquid or vapour, promotes the conducting qualities of bodies. How fitly, therefore, in this Hymn has lightning been associated with clouds! Out of the clouds comes the danger,-out of the clouds, too, comes the water which helps to avert it from us. Dry air is a bad conductor, and favours undue electrical accumulations; but moist air is a good conductor, and drains