CHAP. III. PASSAGE OF " THE BREACH." 67 



experienced this day (seven-tenths of an inch), no very marked 

 effects ensued. The most noticeable points were the lassitude with 

 which we were pervaded, and the readiness with which we sat down. 

 Atmospheric pressure varied little at the third camp. At 6 p.m., 

 on Jan. 2, the mercurial barometer (red. to 32°) read 15 '992 inches, 

 and at 5 a.m., on Jan. 3, 15*974 inches ; but the aneroids con- 

 tinued to lose upon the mercurial, and their mean error on Jan. 

 4-5 had risen to — 0'974 of an inch, from — 0'903 in. when they 

 were last compared at the second camp (see p. 56). Two were 

 already nearly out of range ; another couple were out of order ; and 

 two others alone remained serviceable for yet lower pressures. 



We again started from the third camp on Jan. 4, at 5.40 a. hi. 

 The morning was fine and nearly cloudless, and profiting by the 

 track made on the previous day we proceeded at first at a fair 

 rate and finished the escalade of " the breach " at about eight 

 o^clock. Then bearing away to the left,^ at first over snow and 

 then over snow-covered glacier, we mounted in zigzags, to ease 

 the ascent. The great schrunds at the head of the Glacier de 

 Thielmann were easily avoided ; the smaller crevasses Avere not 

 troublesome ; and the snow was in good order, though requiring 

 steps to be cut in it. Jean-Antoine Carrel led, and my orders to 

 him at starting were that we were to go slowly — the rest was 

 left to his discretion. I noticed, at this stage, that his paces 

 got shorter and shorter, until at last the toe of one step almost 

 touched the heel of the previous one. At about 10 a.m., at a 

 height of 19,400 feet, Ave passed the highest exposed rocks, Avhich 

 Avere scoriaceous lava, apparently in consolidated beds,^ and for 



1 Our track at this part of the ascent is shewn in dotted line upon the view 

 facing p. 24. 



2 Exposed in patches, about twelve feet long, projecting a few feet above the 

 snow. The Carrels got nearly as far as these rocks upon December 29. 



"A slightly scoriaceous lava, rough to the touch, almost purple-black in colour, 

 with numerous very minute specks of a glassy felspar. Except that the base is 

 rendered rather more opaque by disseminated opacite, it does not differ materially 

 from several already described. There are the usual crystals of felspar, one or two 



