204 



NATURE 



{Dec. 29, 1887 



when one of a pair was shot, the other went on feeding as 

 though nothing had happened. 



"The thrush {Turdus erythropleurus) is very abundant, 

 and as tame as possible. None of my specimens show 

 any motthng, but Capt. Aldrich told me that he saw one 

 with the breast mottled. The bill and feet are as yellow 

 as a cock blackbird's. I heard no song,\>w\. they often give a 



' chick chick chick — chick-chick-chick,' quicken- 



ing time at the finish. 



" Parties of twelve to twenty of a species of Zosterops 

 were very common. They had just-fledged young ones 

 among them. 



" The other birds we obtained were two hawks, an owl, 

 a swift, a heron, a plover, and a sandpiper. Besides 

 these, frigate-birds, gannets, boobies, and boatswain-birds 

 of two kinds were everywhere abundant. 



" We obtained three kinds of lizards, and the Typhlops 

 which was found before, but no tortoises. We saw a 

 turtle making off down the beach early one morning, but 

 it got into the sea before it could be turned over. 



" We saw no frogs, and heard none. 



" We found five kinds of land-shells, four of butter- 

 flies, ^ few moths, and some eighteen species of beetles, 

 besides spiders, centipedes, &c. I have one of the 

 hawks alive, which I hope to be able to bring home to 

 England "J. J. LiSTER." 



Accounts have been received from Captain Aldrich, 

 R.N., of H.M. surveying-vessel Egeria, of a recent visit 

 to Christmas Island in the Indian Ocean, made in con- 

 sequence of the interest attaching to the small collec- 

 tion recently brought thence by Captain Maclear, R.N., 

 (see Nature, vol. xxxvi. p. 12). Mr. J, J. Lister kindly 

 volunteered to act as naturalist, and proceeded from 

 England to Colombo, whence he took a passage in the 

 Egeria for the purpose of collecting. 



Captain Aldrich states that the highest point of the 

 island was reached at the expense of considerable labour, 

 but without as much difficulty as was anticipated. This 

 point is 1200 feet high, and not, as was before incorrectly 

 stated, 1580 feet. 



The island is coral-clad to the very top, the actual 

 summit being a block of coralline limestone, worn and 

 undermined. No rock other than of a calcareous nature 

 was met with in the island, though a diligent search was 

 made, and holes dug where the soil appeared thickest. 



Three tiers of cliffs, probably marking sea-levels, inter- 

 vene between the top of the existing sea cliffs and the 

 summit. Breaches in these cliffs afforded means of 

 scaling them, aided by the numerous aerial roots of the 

 trees with which the island is densely covered. 



Between the cliffs the ground rises irregularly, being 

 covered in some places with soil apparently deep, inter- 

 mixed with fragments of coral. Tangled jungle and high 

 forest grow everywhei-e. The vertical rise to the summit 

 where ascended takes place in the following manner, as 

 described by Captain Aldrich : — 



Coast cliff 30 feet vertical. 



Moderate slope 90 ,, 



First inland cliff". 85 ,, 



Moderate slope 250 ,, 



Second inland cliff ) 



Slope [ 95 



Third inland cliff ) 



Steep slope of rough ground 650 ,, 



The total horizontal distance is about 5000 feet. 



Christmas Island therefore appears to be a remarkable 

 instance of the complete casing with coral of an island 

 which, from the time that its nucleus first came within the 

 reef-building zone, has been steadily subjected to a move- 

 ment of upheaval, varied by pauses, during which the 

 cliffs were eroded by the sea. So far as I am aware, no 

 case of similar magnitude has yet been recorded. 



The collections now on their way to England are, it is 

 feared, not so varied as was anticipated from the samples 

 of life brought home by the Flying Fish. 



A considerable number of interesting photographs were 

 obtained by the officers, and accompany Captain Aldrich's 

 report, which will be published. 



The Egeria has obtained a line of soundings across 

 the hitherto unfathomed area of the southern Indian 

 Ocean, between the Strait of Sunda and Mauritius, but 

 no details have as yet come to hand. 



December 17. W. J. L. Wharton. 



TIMBER, AND SOME OF ITS DISEASES} 



II. 



'X* HE enormous variety presented by the hundreds of 

 -^ different kinds of woods known or used in different 

 countries depends for the most part on such peculiarities as 

 I have referred to above, together with some others which 

 have not as yet been touched upon. Everybody knows 

 something of the multitudinous uses to which timber is 

 put, and a little reflection will show that these uses are 

 dependent upon certain general properties of the timber. 

 Speaking broadly, the chief properties are its weight, 

 hardness, elasticity, cohesion, and power of resisting 

 strains, &c., in various directions, its durability in air and 

 in water, and so forth ; moreover, special uses demand 

 special properties of other kinds also, and the colour, 

 closeness of texture, capacity for receiving polish, &c., 

 come into consideration. 



Now, there is no doubt that the structure of the wood 

 as formed by the cambium is the chief factor in deciding 

 these technological characters : it is not the only factor, 

 but it is the most important one. Consequently no sur- 

 prise can be felt that those who are interested in timber 

 have of late years turned their attention to this subject 

 with a view to ascertain as much as possible about this 

 structure, and to see whether it can be controlled or modi- 

 fied, what dangers it is subject to, and how far a classifica- 

 tion of timbers can be arrived at. The more the subject 

 is studied, the more interesting and practically important 

 the matter becomes. The results already obtained 

 (though the study is as yet only in its infancy), have 

 thrown brilliant light on several burning questions of 

 physiology — as witness the researches of Sachs, Hartig, 

 Elfving, and Godlewski, on that old puzzle, to account for 

 the ascent of water in tall trees. The study is, moreover, 

 of first importance for the comprehension of the destruc- 

 tion of timber, due to " dry-rot " and the parasites which 

 cause diseases in standing trees, as is shown by the 

 brilliant researches of Prof. R. Hartig on the destruction 

 of timber by Hymenomycetes ; and again as yielding 

 trustworthy information as to the value of different kinds 

 of timber in the arts, and enabling us to recognize foreign 

 or new woods of value. In support of this statement it is 

 only necessary to call attention to the " Manual of Indian 

 Timbers," prepared for the Indian Government by Mr. 

 Gamble ; or to refer to the beautiful series of wood- 

 sections prepared by Nordlinger. 



It is, of course, impossible in an article like the present 

 to do more than touch upon a few of the more interesting 

 points in this connection ; but I may shortly summarize 

 one or two of the more striking of these peculiarities of 

 timbers, if only to show how well worth further investiga- 

 tion the matter is. 



Many timbers, from both tropical and temperate 

 climates, exhibit the so-called " annual rings " on the 

 transverse section ; but this is not the case with all. 

 Most European timbers, for instance, are clearly com- 

 posed of such layers ; but in some cases the layers 

 (" rings " on the transverse section) are so narrow and 



' Continued from p. 186. 



