60 CLEARNESS OF THE ATMOSPHERE, 



Jan. ^th, 1860. — Our passage to the Duch^teau 

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

 protracted by the prevalence of Hg-ht winds, althoug-h 

 these were generally favourable, or from the west- 

 ward. Occasional calms, squalls, and rain occurred, 

 but the weather generally 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 during a light breeze from the north- 

 west we clearly saw Mount Yule (10,046 feet high) 

 and the summit of Mount Owen Stanley, distant 

 respectively, one hundred and twenty, and eighty 

 miles from the ship. On this occasion also we had 

 a fuU view of the whole of Mount Astrolabe, which 

 although 3824 feet in greatest height, and appear- 

 ing to D'Urville as he ran past to be the highest 

 land on this portion of the coast, is rendered quite 

 insignificant by the lofty though distant range 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 line and distant from it about eight miles. 

 Viewed from the south-westward the outline is regxi- 

 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 



