My friend Mr. Hirst took charge of the instrument, and on the 28th of July I fixed a single stake beside the Grand Moulin, in a straight line between a station at Trelaporte and a well-defined mark on the rock at the opposite side of the valley. On the 31st, the displacement of the stake amounted to 50 inches, and on the 1st of August it had moved 74-1/2 inches--the moulin, to all appearance, occupying throughout the same position with regard to the stake. To render this certain, moreover we subsequently drove two additional stakes into the ice, thus enclosing the mouth of the shaft in a triangle. On the 8th of August the displacements were measured and gave the following results:-- Total Motion. First (old) stake 198 inches. Second (new) do. 123 " Third 124 " [Sidenote: MOTION OF THE MOULINS.] The old stake had been fixed for 11 days, and its daily motion--_which was also that of the moulin_--averaged 18 inches a day. Hence the moulins share the general motion of the glacier, and their apparent permanence is not, as has been alleged, a proof of the semi-fluidity of the glacier, but is due to the breaking of the ice as it passes the place of local strain. [Sidenote: DEPTH OF "GRAND MOULIN" SOUGHT.] Wishing to obtain some estimate as to the depth of the ice, Mr. Hirst undertook the sounding of some of the moulins upon the Glacier de Lechaud, making use of a tin vessel filled with lumps of lead and iron as a weight. The cord gave way and he lost his plummet. To measure the depth of the Grand Moulin, we obtained fresh cord from Chamouni, to which we attached a four-pound weight. Into a cavity at the bottom of the weight we stuffed a quantity of butter, to indicate the nature of the bottom against which the weight might strike. The weight was dropped into the shaft, and the cord paid out until its slackening informed us that the weight had come to rest; by shaking the string, however, and walking round the edge of the shaft, the weight was liberated, and sank some distance further. The cord partially slackened a second time, but the strain still remaining was sufficient to render it doubtful whether it was the weight or the action of the falling water which produced it. We accordingly paid out the cord to the end, but, on withdrawing it, found that the greater part of it had been coiled and knotted up by the falling water. We uncoiled, and sounded again. At a depth of 132 feet the weight reached a ledge or protuberance of ice, and by shaking and lifting it, it was caused to descend 31 feet more. A depth of 163 feet was the utmost we could attain to. We sounded the old moulin to a depth of 90 feet; while a third little shaft, beside the large one, measured only 18 feet in depth. We could see the water escape from it through a lateral canal at its bottom, and doubtless the water of the Grand Moulin found a similar exit. There was no trace of dirt upon the butter, which