4i: 



NATURE 



[March 3, 1881 



be good grounds for believing that they were idols ; but had I 

 been left without help to interpret for myself I should not have 

 guessed them to be net sinkers, but rather children's playthings 

 — tlie ancient representatives of modern dolls. To show how 

 little pains are sometimes taken in the preparation of net-siukers, 

 I may mention that a few months ago, while walking aloni; the 

 banks of the River Bann, I faw a fisherman cutting the tough 

 sward into pieces about two inches by three or fom-, which, in 

 answer to my inquiry, he informed me were intended for net- 

 sinkers. I asked him why he did not use stone or lead, and he 

 replied that turf sinkers were much superior, as in using them 

 the nets never became entangled in ihe bottom of the river. I 

 wonder if this custom is a recent invention or a survival from 

 earlier times. 



I was struck by the close resemblance which several other 

 objects in the Schliemann collection bore to Irish antiquities. I 

 have noted several tool-stones with the usual hollowed marks on 

 the sides, especially those bearing the double numbers 26 and 

 157S, 26 and 147S, 26 and 1522, 45 and 1499, and also a stone 

 celt or hatchet wiih marks on the sides like those on the tool- 

 stones, and hammered at the edge, numbered 13 and 1505, all of 

 which I could match from my own collection. Several wliorls are 

 marked in my notes as being similar to others found in Ireland, 

 and an object bearing the numbers 6 and 1636 as being almjst 

 identical with double stone beads in my collection. I have also a 

 large series of rubbing or polishing stones similar to others in 

 Dr. Schliemann's collection. Hammer-stones numbered 6 and 

 7268, 26 and 1529, 26 and 1566, 13 and 1570 are perfect dupli- 

 cates of some of those found by myself, with flint and bone 

 implements, &c. , at PortstevvarLand Ballintoy. The ornamenta- 

 tion on a few of the stone and glass whorls and beads in my 

 collection have a soit of resemblance to that on some of the 

 terra-cntta whorls exhibited by Dr. Schliemann. 



CuUybackey, Belfast, February 10 W. J. Kno\yles 



Selenium 



The use cf selenium for the automatic registry of star transits, 

 proposed by nre in a letter which you were good enough to 

 publish in Nature, vol. xxiii. p. 218, leads to the idea of 

 applying it in a somewhat similar way lor photometric pur[io-es, 

 in order to improve the existing scale of star magnitudes, and to 

 watch any variations therein. W. M. C. 



Bombay, February 5 



A CHAPTER IN THE HISTORY OF THE 

 CONIFERS 

 'T^HE Sequoias form the third genus of the Taxodieae 

 -•- in the " Genera Plantarum." The only existing spe- 

 cies are the Wellingtonia and the Red-wood of Calilornia, 

 both of which are confined to the south-west coast regions 

 of the United States. Their nearest living allies are 

 Taxodium and Glyptostrobus ; but these were as com- 

 pletely differentiated in the Eocene as at present, and 

 they all appear, like the Ginkgo, to be survivals from 

 more ancient floras ; Sequoia especially had formerly a 

 far wider range than it has at the present day. 



The Sequoias are monoecious, and have obtusely ovate 

 ligneous solitary and terminal cones one to two inches in 

 length, which are persistent and gaping after sheddmg 

 the seed. The scales are spirally disposed, sixteen to 

 twenty in number, wedge-shaped, with an orbicular or 

 transversely oblong nail-like head, depressed, wrinkled, 

 and mucronate in the centre, sharing thus to some extent 

 the ornamentation which seems a characteristic of the 

 Taxodieas. The foliage is distichous and yew-like in 

 Sequoia sempcrvireits, and spiral and imbricated in .i'. 

 gigantca, but both occasionally foliate in the opposite way. 

 The former, or red-wood, occupies the Coast Range, a 

 sandy rock rising to 2000 feet, of supposed Cretaceous 

 age,and forms dense forests twenty to thirty miles in width, 

 from a little south of Santa Cruz to the southern borders 

 of Oregon, following the coast line for some 350 to 500 

 miles, its distribution depending, according to Prof. 

 BoLander, upon the sandstone and oceanic fogs. The 

 S. gigaiitea extends at intervals along the western slope of 



the Sierra Nevada for nearly 200 miles, and at elevations 

 of 5000 to 8000 feet. " Towards the north the trees 

 occur as very small, isolated, remote groves of a few 

 hundreds each, most of them old and interspersed 

 amongst gigantic pines, spruces, and firs, which appear 

 as if encroaching upon them ; such are the groves visited 

 by tourists (Calaveras, Mariposa, &c.). To the south, on 

 the contrary, the Big-trees form a colossal forest forty 

 miles long and three to ten broad, whose continuity is 

 broken only by the deep sheer-walled caiions that inter- 

 sect the mountains ; here they displace all other trees, 

 and are described as rearing to the sky their massive 

 crowns ; whilst seen from a distance the forest presents 

 the appearance of green waves of vegetation, gracefully 

 following the complicated topography of the ridges and 

 river-basins which it clothes." ' The leaves are scale- 

 formed, rounded dorsally, concave on the inner face and 

 closely inlaid, regularly imbricated on the branchlets, 

 longer and looser on the branches. In young trees they 

 are much larger and freer, with long and awl-shaped leaves 

 at an acute angle to the stem. No trees under cultivation 

 in this country seem yet to have completely assumed the 

 small imbricated foliage characteristic of the giant trees of 

 California. 



Although the types of foliage in the two existing species 

 appear to be perfectly distinct, they are not really entirely 

 so ; for .S". seuipervirciis preserves the spiral scale-like 

 leaves for a short distance at the base of each branchlet, 

 and 6'. gigantea sometimes assumes the distichous arrange- 

 ment. Besides, the foliage of the former is not in two 

 rows as it is in Taxodium, being spirally arranged round 

 the stem ; but the leaflets, where they are .flat and 

 comparatively expanded, have a strong tendency to crowd 

 into two marginal rows, so that every surface becomes 

 exposed to light and moisture. The leaflets take a half 

 twist near their base, and then diverge upward or down- 

 wards towards the sides of the branchlet, an additional 

 row frequently lying centrally along the branch. 



The earliest-known Sequoias are Cretaceous, and were 

 described by Carruthers, one as6". Woodwardiihom Black- 

 down, and others as S. Gardncri and .S". ovalis from the 

 Folkestone Gault. The foliage from the latter has falcate 

 leaves like Araucaria, and it is only inferred that it and 

 the cones belonged to the same trees. It is not impossible 

 that the cones may have been brought down from some 

 high ground, and the foliage been shed by trees nearer 

 the sea-level. Although Sequoia itself cannot be traced 

 farther back than the Cretaceous, Schimper speculates on 

 its probable derivation from some much older Araucarian 

 form, and believes its position to be between the Cupres- 

 sineas and the Abietinea;. 



Saporta regards the Chalk period as the age of Sequoias, 

 and our principal knowledge of them is derived from 

 Heer's " Flora fossilis arctica," where a large number are 

 figured. Saporta speaks of Pattorfik as a Sequoia wood 

 carpeted with ferns, and Ekkorfat as a forest composed 

 of cycads, sequoias, and firs. .S". Reitjienbacliiixi the chief 

 form, and occurs in the Cretaceous of Kome, Spitzbergen, 

 and doubtfully at Atane. The foliage resembles the 

 larger foliage of .V. gigantca, being spiral, awl-shaped, 

 set at an acute angle to the stem, and with the points 

 overlapping. It differs in being less regularly spiral, and 

 often combines an approach to the more distichous 

 S. sempe7'virens type, being called in such cases, S. 

 Smittiana. In several of the figured specimens from the 

 Komeschichten the branchlets of the two forms are almost 

 united, and a very slight degree more care in collecting 

 would, it seems, have placed the reality of the union 

 beyond the possibility of doubt. One instance is repro- 

 duced from plate xx., and a fragment from the same plate 

 determined as .$■. Reiclienbachii, to show that even apart 

 from the frequent association of the two species on the 

 same slabs, their distinctness cannot be maintained if the 



s Lecture before Royal Institution, April iz. 187S, by Sir J. Hooker. 



