drought, which is of ultimate importance to the farmers' crops and vegetation in general. It will be seen that all our deductions have been drawn largely from the known facts from observations.

The experiments of L. Fantiat and A. Sartiaux (Translation of a communication to the French Academy of Sciences, Pop. Sci. Monthly for June, 1875), which have come to the notice of the writer since the above has been written, are of great value as well as interest. Space is wanting to give at any length the experiments of these authors. They say: "We now made the following observations in the heart of the forest of Helatte, which embraces 5000 hectares of land. At the height of about six meters (say twenty feet) above a group of oaks and hornbeans eight or nine meters high, we placed a pluviometer, pscychrometer, maximum and minimum thermometers, and an evaporometer, so as to ascertain at that point the amount of rainfall, the degree of saturation of the air, and the rate of temperature and evaporation. In open air at a distance of only 300 meters from the forest, and at the same height above the ground as in the former case, we placed similar instruments under the same conditions. With regard to the rainfall and degree of saturation, the observations for six months showed the total rainfall to be 192.50mm in the forest and 177mm in the open air, difference in favor of the forest, 15.50mm. The degree of humidity for the open air showed a mean of 61.7, and in the forest 63°, difference in favor of the forest, 1.3°." These investigations are, in a measure confirmatory of my own.

Forests produce abundant dews. The formation of dew is dependent on two conditions, the radiation from objects near the earth and a certain proportion of moisture in the air. Just as in the case of the production of rain, the moister the air the more readily is dew formed, it requiring a less reduction of temperature, hence when the moistened atmosphere in the vicinity of a forest comes in contact with the night air, dew in abundance is the result. Having shown that the temperature of the trees, their leaves and the atmosphere in the woods is several degrees lower than the air without, it may be inferred that dew is frequently formed during the day in the shade, and, perhaps, over the forest, particularly when the atmosphere is tranquil or when there are but slight breezes, shedding its silent enlivening influence to fields and valleys round about. This is another office on,

the part of forests not by any means to be despised, since heavy dews are often very refreshing in their effect upon vegetation, and doubtless add to the fertility of the soil in many instances. It is an observation worthy of note, too, that in some parts of the globe nearly all the moisture that reaches the earth is in the form of dew, e. g., Egypt and Arabia.

It should be recollected that the action of forests, in every aspect considered, is more or less local in character. It follows, therefore, that the local distribution of woods is of the utmost importance. Our investigations likewise show the necessity for forest culture in regions where a proper proportion (from twentyfive to thirty per cent.) does not exist for their real benefit to the climate, while on the other hand they exhibit with equal force the folly of the ravages of the woodman's axe in destroying our primitive forests.

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GLACIAL MARKS IN LABRADOR.

BY A. S. PACKARD, JR.

HE engraving' illustrating this article, brings out clearly some of the characteristic features of the scenery of the coast of Labrador. In the foreground the rocky shore of the Horsechops, as the deep fiord is called, which is situated far up on the eastern coast of Labrador, has been ground down, smoothed and polished by the great mass of land ice which formerly filled Hamilton bay and moved slowly down from the table-land in the interior, and whose ice front must have presented to the sea a wall, perhaps 500 to 1000 feet high, at the end of which was probably a submarine bank or terminal moraine like those known to exist at the present day on the coast of Greenland and Spitzbergen.

Across the fiord on the shores of the bay, which rise abruptly in great rocky terraces-also a characteristic feature of Labrador and Arctic landscapes-may be seen scattered snow banks, which linger on these shores as late as August, while those in the more shaded, protected places may live on until the early snows in September give them a renewal of life, so that their existence may become perennial.

1 From a photograph kindly presented to the author by William Bradford, Esq. The writer here acknowledges, with pleasure, the many facilities and kindnesses received during a voyage with this enthusiastic artist to the Labrador coast in 1864.

In this inhospitable, rigid climate, where the Arctic current passing out of Baffin's bay presses against the coast, bearing on its surface an almost continuous expanse of floe ice, forming a belt perhaps 500 to 1000 miles long by from fifty to sometimes one hundred miles wide, the temperature of the Labrador coast north of Belle isle is kept down to the average annual of 32° Fahrenheit, so that the climate of the more exposed parts of the coast of Labrador, particularly the capes and islands, is nearly identical with that of Southern Greenland. Indeed, many of the insects, the birds and mammals, as well as the flowers, are the same as those of Greenland.

At the head of the bays and fiords, where the soil is protected from the chilling influences of the damp casterly winds which blow inland over the belt of floe ice fringing the coast, the spruces attain a growth some twenty and thirty feet in height, and the flora and fauna is, in general, more like that of the region lying near the limit of trees in the interior of British America.

On the left side of the foreground is a hut of some squalid fisherman's family, built of hewn spruce logs, banked up on the sides and with the roof partially covered with sods from the wet peaty soil. Judging from the houses of the Labrador fishermen we have entered, the interior is as dark and dismal, as forbidding and comfortless as can well be imagined, though this is not true. of many of the homes of the Labrador folk.

Now the question arises, why may not this smooth, polished rock-surface have been made so by the floating ice borne down by the strong Labrador polar current, which flows past the coast at the rate of three or four knots an hour? That it had been done by land ice moving down the bay from the interior, we have been able to prove by our observations at " Indian Tickle," a deep, narrow fiord separated by a point of land from the northern side of Hamilton bay, or Invuctoke inlet. A "tickle," to use the language of the Labradorian, is any deep, narrow bay, just wide enough to admit of a vessel's passing through it. The shores of the Indian tickle presented much the same appearance, for here the Domino quartzite, very smoothly worn and polished, in places capped by trap overflows, runs under the water to the depth of about thirty feet, forming a polished and smooth bottom to the harbor. The marks we observed, and which proved conclusively to our mind the course taken by the ice, occur about twenty-five

feet above the water's edge, and below the line of lichens, which are probably kept at a distance by the sea spray.

Here on the polished and smooth shore, somewhat like that represented in Plate III, we observed a number of remarkable lunoid furrows (Fig. 1). These crescent-shaped depressions ran at exactly right angles to the course of the bay, and were from five to fourteen inches broad by three to nine inches long, and the depression was deepened in the hollow of the curve, for

FIG. 1.-Glacial lunoid furrows at Indian Tickle, Labrador.

about an inch. Their inner, or concave, edge pointed south-west, the bay running in a general S. W. and N. E. direction. They were scattered irregularly over a surface twenty feet square. Where several followed in a line, two large ones were often succeeded by a couple one-quarter as large, or vice versa. Also at Tub island on the southern side of Hamilton bay, similar markings, though less distinct, occurred about the same distance above the sea, and on a similar polished quartzite.

These marks agree precisely with a number of lunoid furrows which I have observed on a shoulder of rock near the summit of

Mount Baldface, in the White mountains, which is 3600 feet high, and at other points in the White mountains, where I could observe the course of the ancient glaciers by trains of boulders and also by glacial grooves. These peculiar lunoid furrows are evidently made by rounded boulders freezing into the bottom of the glacier; the stone being thus frozen solidly into the ice, serves as a rude gouge, wearing out a crescent-shaped depression. The succession of several such furrows appears to be the result of the stone's slipping from the ice and turning over and becoming frozen in again during the advancing and receding motions of the glacier.

The presence, then, of these furrows is good evidence that the ice moved down the bay seaward. They could not have been made by floe ice, as the polar current flows along the coast at right angles to the direction of the bay, while it also appears that similar marks are abundant on the summits of some of the White mountain peaks. In a future paper I shall have more to say of glacial phenomena in Labrador.

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EDITORS' TABLE.

EDITORS: A. S. PACKARD, JR., AND E. D. COPE.

The intelligent press of the country is gradually adopting the position taken by the NATURALIST, in its August number, on the question of the insanity of Guiteau, the murderer of President Garfield. This is, that whether legally insane or not, the mental condition of the prisoner falls within the boundary-line of insanity.

This was simply an adaptation of the well known views of Herbert Spencer and Dr. Maudsley. It is to be hoped that a full investigation of Guiteau's case will lead to an important modification of the legal definition of insanity, and of the laws relative to the treatment of insane criminals. In the first place, the present definition, which only admits insanity where the criminal is unable to judge of the consequences of an act, is certainly erroneous. Persons undoubtedly insane often act with deliberate design, and great forethought. It would be a safe, though not a perfect definition of insanity, to describe it as a state of mind in which acts are committed, which are in direct opposition to the plain and obvious interests, not of persons affected by the act, but of