490 



NATURE 



[March 26, 1896 



Descartes with regard to the law of this refraction, he 

 was probably anticipated, and by a much longer interval. 

 His Planisphere and other smaller works scarcely call 

 for notice. On the whole, it may be said that Ptolemy 

 was rather a collector and condenser of the scientific 

 facts and methods than an original discoverer or inves- 

 tigator. And with all proper Baconian admiration for 

 the wisdom of the ancients, we may be thankful that in 

 our time, at least in the domain of natural science, the 

 wisdom of the modems has been added to it. 



W. T. Lynn. 



A VIEW OF KILAUEA. 



'T^HE interest of Kilauea is perennial. Popocatapetls 



•*■ may arise in a night, or Krakatoas may be blown to 



shivers, and attention may thus be temporarily withdrawn 



banana, and past clumps of screw-pine {Pandanus). At 

 the height of about looo metres the tropical vegetation 

 is left behind ; trailing Freycinetias and great Cibotias 

 give place to tree ferns and an undergrowth of plants of 

 temperate affinities, such as cranberries {Vaccinium). 

 On the north-eastern edge of the crater, at the height of 

 1230 metres, is a good hotel, in telephonic communi- 

 cation with the coast. Dr. Friedlaender's description of 

 the mountain takes us over a good deal of old ground ; 

 but his account records recent changes, and his notes and 

 views bring out several characteristic features of the 

 volcano. In the first place he emphasises the fact that 

 though Mauna Loa rises to the height of the Jungfrau, 

 neither it nor Kilauea have any claim to be called 

 mountains. Whereas some of the Italian volcanoes have 

 slopes of 30'', that of Mauna Loa is only 6°, and that from 

 the summit of Kilauea to the north-east cape of the 



a) Hut. {b) Margins of the secondary crater, (c) Margins of the primary crater, (rf) Secondary crater, {c) Primary 



from the great Hawaiian volcano. But such cataclysms 

 are exceptional. Kilauea, on the other hand, is always 

 available to the student of vulcanicity, while Dutton's 

 beautifully illustrated memoir, and Dana's great mono- 

 graph enable observers to use their opportunities to the 

 fullest advantage. Dr. Benedict Friedlaender's papers 

 in Hiinmel unci Erde (Bd. viii. 1895) are the latest addi- 

 tion to the extensive literature upon this subject, and give 

 a series of photographs, which are a useful supplement 

 to those of the two American authors. Dr. Friedlaender's 

 narrative shows that the mountain can now be studied 

 without inconvenience. A good track runs from Kilo, on the 

 north-eastern coast of Hawaii, to the summit of Kilauea. 

 It passes first through plantations of sugar-cane and 



NO. 1378, VOL. 53] 



island is only 1° 35'. The summits of the volcanoes are 

 not mountain summits, but only a high plain. Orogra- 

 phically, Kilauea is only a lateral crater on Mauna Loa ; 

 but geologically they must be regarded as two distinct 

 volcanoes, as eruptions sometimes take place on Mauna 

 Loa, while the lava lake in the other is at rest. As 

 Mauna Loa is 3000 metres higher than Kilauea, and the 

 weight of a column of basaltic lava of that length 

 is 900 atmospheres, this independence of the two volcanic 

 centres appears at first sight to be in contradiction to the 

 fundamental principles of hydrostatics. The author 

 explains this by the assumption, that the lavas in the 

 central pipe of Mauna Loa are of lower specific gravity 

 than those of Kilauea, owing to the greater abundance of 



