00 CLEARNESS OF THE ATMOSPHERE. 



Jan. 6th, 1850. — Our passag-e to the Duchdteau 

 Isles, a distance of less than 400 miles, has been 

 protracted by the prevalence of lig-ht winds, althoug'h 

 these were g-enerally favourable, or from the west- 

 ward. Occasional calms, squalls, and rain occurred, 

 but the weather g-enerally was finer than during" the 

 S. E. monsoon. As an instance of the clearness 

 of the atmosphere, so different from what we 

 had usually experienced during- our former visit 

 to these shores, it may be mentioned, that on one 

 occasion dm'ing- a hg-ht breeze from the north- 

 west we clearly saw Mount Yule (10,046 feet hig-h) 

 and the summit of Mount Owen Stanley, distant 

 respectively, one hundred and twenty, and eig-hty 

 miles from the ship. On this occasion also we had 

 a full view of the whole of Mount Astrolabe, which 

 althoug-h 3824 feet in greatest heig-ht, and appear- 

 ing- to D'Urville as he ran past to be the hig-hest 

 land on this portion of the coast, is rendered quite 

 insig-nificant by the lofty though distant rang-e be- 

 hind. Mount Astrolabe differs in character from 

 any other of the New Guinea mountains seen by us, 

 indicating a different geological formation. The 

 summit extends thirteen miles, running parallel with 

 the coast Hne and distant from it about eight miles. 

 Viewed from the south-westward the outline is regu- 

 lar, exhibiting a series of nearly flat tops with slight 

 interruptions, but from the southward it appears as a 

 succession of terraces or projecting cliffs, precipitous 

 in front near the summit, with a long steep slope 



