site direction and at the same level the outlines were totally different, showing merely a succession of terraces or steps inclined

inward toward the glacier and broken by longitudinal crevasses. The annexed sketches were made from this point of view. No. 1 is taken looking up the river, over the end of the glacier, and

shows the pyramids of ice. The line of ponds, and the two moraines are seen at the base, and the river on the extreme

right. No. 2 shows the appearance of the glacier in the opposite direction. A broad fissure between one level of the ice and the next is filled with snow.

Bluffs of ice. End of Glacier, looking toward the southeast.

It is evident that this glacier breaks down in a series of great steps or ledges along the greater part of its front. These steps rise for 20 to 30 feet one above the other and thus produce a stair-like ascent, while at the same time the numerous parallel fissures at right angles break the surface into rectangular blocks, which on the side exposed to the sun soon become worn into the pyramids and cones. The difference of outline in opposite directions is thus explained.

I was inclined to regard the melting action of the water of the river as the cause of this abrupt breaking off of the end of the glacier. There may, however, be a sudden break in the rock foundations at this point, so as to produce an ice-cascade. The following section will perhaps give a clearer idea of the manner in which the glacier breaks down,

Section of end of glacier.

One or more streams descend under the glacier, and reach the river at different places. The rushing and roaring sound was rather startling at some of the crevasses.

Judging from the number of loose blocks of rock at the foot of the glacier, the upper surface must be strewn with them, but this could not be verified by observation. Time did not permit a more extended examination. There would be little difficulty in gaining the surface of the glacier from the side, and, perhaps, at some other points along its front. It was impossible to get our Indian guide to accompany us. They have a tradition of the loss of one of their chiefs upon this glacier.

The ancient terminal moraine of this glacier is significant of an amelioration of the climate. It is also interesting to note the effect which this accumulation of materials from the glacier has had upon the river. It has acted as a dam for the waters, setting them back in the valley for some distance.

In this connection the following notes upon the occurrence of great bodies of ice, undoubtedly glaciers, in the more northern parts of Russian America have a special interest.

According to Sir Edward Belcher* the shores of Icy Bay at the foot of Mount St. Elias, lat. 60°, are lined with glaciers. "The whole of this Bay, and the valley above it, was found to be composed of (apparently) snow-ice, about 30 feet in height at the water cliff, and probably based on a low muddy beach." At Cape Suckling in the same latitude and west of Icy Bay the

* Voyage of the Sulphur, i, 78-80.

same voyager observed a vast mass of ice sloping to the sea, the surface of which presented a most singular aspect, being "one mass of four-sided truncated pyramids.' He was not able to

account for this and observes "What could produce these special forms? If one could fancy himself perched on an eminence about 500 feet above a city of snow-white pyramidal houses, with smoke-colored flat roofs covering many square miles of surface and rising ridge above ridge in steps, he might form some faint idea of this beautiful freak of Nature."

Vast bodies of ice terminating in cliffs upon the sea are numerous in Prince William Sound, and the thundering noise of the falling of large masses of ice was heard by Vancouver.*

On the shores of an arm of Stephens Passage (northwest of Sitka) a compact body of ice extended for some distance at the time of Vancouver's visit, and from the rugged valleys in the mountains around, immense bodies of ice reached perpendicularly to the sea, so that boats could not land. Similar observations are made, in general, of the mountains of the coast opposite Admiralty island. Two large open bays north and west of Point Couverdeen are terminated by solid mountains of ice rising perpendicularly from the water's edge.

From these various observations we may conclude that the mountain region of Russian and British North America, from latitude 55° to the Polar sea, is dotted with glaciers cutting and scoring the mountains as they descend, and pushing their accumulations of rocky debris either into the ocean, or the rivers of the interior.

SCIENTIFIC INTELLIGENCE.

I. CHEMISTRY AND PHYSICS.

1. On the influence of the adhesion of vapor in experiments upon the absorption of heat.-The subject of the absorption of radiant heat by aqueous vapor has been again taken up by Magnus who has succeeded in pointing out the source of error which affected the experiments of Tyndall and of Wild. In a previous memoir Magnus had endeavored to shew that vesicular vapor absorbs heat more powerfully than dry air, but that air loaded with transparent vapor has no greater absorptive power than air which contains no vapor at all. Tyndall replied to this paper, and the subject was then examined independently by Wild, who fully confirmed the results of Tyndall. In his new investigation Magnus employed an apparatus of the same dimensions with that of Wild and of similar construction. Experiment soon proved that the walls of the tubes containing the dry or moist air through which the radiant heat passed exercised a * Vancouver's Voyages, iii, 185, (1794), quoted by Findlay, Directory of Pacific Ocean, i, 479.

Pogg. Ann., cxxix, 57.

⚫ powerful influence upon the absorption. Thus a tube coated internally with lamp-black produced an effect precisely the opposite of that which was observed when a polished tube was employed. In this case an increase in the amount of heat transmitted was observed when moist air was blown into the tube and a diminution with dry air, while the contrary takes place when a polished tube is used. Magnus proved that a layer of water is deposited upon the inside of the tube throughout its whole length, by shewing that the tube itself becomes warmer whenever moist air is thrown in. This layer of water absorbs more heat than the polished wall of the tube would do if dry, and consequently reflects less to the thermo-electric pile. Experiment showed that the quantity of heat reflected to the pile by the dry wall of a polished brass tube filled with dry air was about six times as great as that which the pile received directly when the tube was removed. Every diminution in the reflecting power of the tube must therefore greatly diminish the quantity of heat received by the pile. In a blackened tube the particles of carbon act as absorbents like the particles of water, only in a higher degree, consequently their absorption is but little increased by the deposition of water.

Hence there is no sensible cooling when moist air is blown into a tube lined with velvet or blackened inside, but on the contrary a rise of temperature which depends on the heat given out by the condensation. By employing two concentric tubes the space between which could be filled with water at different temperatures, Magnus found that when the inner tube had exactly the temperature of the air blown into it, it behaved precisely like the brass tube mentioned above. When the temperature of the inner tube was a few degrees lower than that of the moist air thrown in, the temperature of the pile diminished in a very marked degree, but reached its minimum much more slowly than when the tube had the same temperature as the air thrown in. This doubtless arose from the fact that the greater quantity of condensed vapor made a greater quantity of moist air necessary, the admission of which required a longer time. Further experiments distinctly proved that a condensation of vapor upon the walls of the tube took place even when the moist air blown in was far from its point of saturation. The vapors of alcohol exhibited the same phenomena as those of water, only in a higher degree. In addition, however, it was found that the vapor of alcohol itself exerts a powerful absorbent action upon radiant heat, which is not the case with the vapor of water. The author concludes from his experiments, that the apparent absorption of heat by aqueous vapor observed by Tyndall and Wild is due simply to the effect of the condensation of water upon the sides of the containing tubes, and not to any specific absorptive power in the vapor itself.-Pogg. Ann., cxxx, 207.

W. G.

2. On fluosalts of antimony and arsenic.-MARIGNAC has examined the action of fluohydric acid upon antimonic and arsenic acids and the corresponding salts. Antimonic acid dissolves in fluohydric acid and gives a fluorid which could not be obtained crystallized but which may be evaporated to a gummy consistency. This fluorid unites readily with alkaline fluorids to form crystalline salts, which are very soluble and more or less deliquescent, their solutions are not precipitated—at least at first— by acids, sulphuretted hydrogen, caustic alkalies, or carbonates. The crys