442 



NA rURE 



{Oct. I, 1874 



that way with very considerable differences, and so true thai 

 those surely are not the kind of things to which Mr. Darwin 

 looks as difficulties to overcome, but as stepping-stones in his 

 way." 



Chuiiil Phciioinaia in the Siena Nezmfa, by Prof. John Muir, 

 of Oakland, Cal.— The studies of Prof. Muir referred particu- 

 larly to that portion of the Sierra which is embraced between 

 lat. 36" 30' and 39°, which measures about 200 miles in length 

 by about 60 in width, and attains an elevation along the axis 

 from S,6ooft. to nearly 15,000 ft. above the sea. All the indi- 

 vidual mountains distributed over this vast area, of whatever 

 kind, have Ixcn brought into relief during the glacial epoch by 

 llie direct metbanical action of the ice-sheet and the glaciers into 

 wliich it afterwards separated. The chief phenomena presented 

 are :— (i) scratche I and polished suifaces, (2) moraines, (3) mou- 

 tonned rock-forms, and sculpture in general, as seen in valleys, 

 ridges, lake basins, and separate mountains. 



T he paper goes on to describe the lofty mountains distributed 

 along the summit of the portion of the Sierra under considera- 

 tion, which are almost wholly unexplored — Mounts Dana, Lyell, 

 Whitney, and Tyndall. The pinnacles, which are the smallest of 

 the summit mountainels, are desciibed in an interesting way, the 

 author concluding that instead of each being formed by special 

 upheaval, or supposing that the chasms which separate them 

 were made by subsidence, they were formed by the removal of 

 the materials which once filled the intervening chasms. The 

 same truth applies to the larger peaks, and the author concludes 

 this branch of his subject by saying that they are all residual 

 masses of the once solid wave of the entire range, and all that 

 would be required to obliterate their distinctive character would 

 be the restoration of .the materials which have been carried 

 aw ay. 



The next in<iuiiy is, what has become of this material, not the 

 millionth pait of which can now be seen? and the author answers 

 himself with the statement that glaciers were the transporting 

 agents, and that in forming the basins and valleys in w-hich they 

 flowed, they carved out flic summit peaks. This is so important 

 a proposition as to demand careful attention to its proof. This 

 proof is brought forward in detail. Subsequently, granting this 

 proposition to be true from the proof, the author is obliged to go 

 on to show %\ hat force or forces have sharpened the crests, which 

 bear no trace of glacial action, and which were probably always 

 above its reach. Next is considered the formation of special 

 groups cf mountains, and the geological effects of shadows— in 

 prolonging and intensifying the actions of portions of glaciers, 

 as shown in moraines, lake basins, and in the difference in form 

 and sculpture between the north and south sides of valleys and 

 mountains; especially as to their effects in the segregation of 

 mountain masses. Also as to the effect of physical structure 

 upon surface features, and the cause of the absence of well- 

 matked individuality in summit mountains. 



Prof r. W. Clarke, of the University of Cincinnati, read a 

 paper On the Moh-cidar Volume of Water oj CrystalUsatwn. He 

 stated that, to the chemist, it is important to get at some distin- 

 gui'hlng character between water of crystallisation and true 

 water of hydration. This character may be found by a study of 

 the molecular volumes of various hydrated compounds. If we 

 determine the molecular volume of frozen water, that is ice, we 

 shall find it to be I9'6. If that water unites to form a hydrate 

 or a crystalline salt, contractron ensues, and by studying that 

 contraction we get at curious resuUs. In the case of water of 

 crystallisation. Prof. Clarke has studied over thirty salts, and in 

 every case the molecular volume of the water is about 14. With 

 water of hydratim no such regularity is found. Evidently, then, 

 when water unites with an anh) drous salt from water of crystal- 

 lisation, all the condensalioir which occurs is on the part of the 

 water, ihe volume of the molecule of the salt itself remaining 

 unchanged. 



Prof. Clarke also read a paper On ihe Molecular Heat of Simi- 

 lar Compounds. Prof Clarke said that it is commonly thought 

 that S'miJar compounds have equal molecular htat. This is only 

 approximately Itue. In compaiiiig about twenty series of similar 

 comjiounds, Prof. Clarke finds that the molecular heat increases 

 slightly with the molecular weight, though in a very different 

 ratio. In comparing all the extant determinations of specific 

 heat, he has found only two or three exceptions to this rule, and 

 even they were doubtful. 



Prof. K. E. Rogers, of the University of Pennsylvania, 

 read a A'olicc of J'rof. A. A'. Eaton's nan Compound Onc- 

 frisin Spectroscope. The instrtiment is the inveiUion of a 

 Brooklyn^ chtmisf,' and is by himself named "a direct-vision 



spectroscope." It consists of a thick plate of glass with parallel 

 sides, united to one of the faces of an ordinary bisulphide of car- 

 bon prism, or a prism of dense flint-glass. According to the 

 amount of dispersion desired, the light is made to enter either 

 on the end of the glass plate or on the opposite face of the 

 bisulphide prism. The results obtained from this instrument are 

 as follows ; — The dispersion of this compound prism is nearly 

 four times greater than that of the ordinary 60° prism. The 

 mean emergent ray is practically parallel to the incident ray. 

 It does not deflect the ray from its original path. Many 

 Frauenhofer lints are visible by this prism with the naked eye, 

 while with the observing telescope all the prominent lines are 

 clearly reversed, without the use of the slit or collimator, by 

 merely throwing a strong beam of light by means of a mirror. 



Dr". J. ri. Mellichamp, of Blufflon, S.C., gave an account of 

 some recent observations at Blulifton upon the Sarracenia vario- 

 laris, which abounds in that locality. Th's species of the pitcher 

 plant has an elongated, conical, erect leaf, with a broad lamina 

 curved over the opening, and a wide longitudinal wing upon one 

 side the whole length of the tube. The upper portion is veined 

 with purple, the intervening spaces being white and diaphanous. 

 Dr. Mellichamp estal-ilishes the following points : — The base 

 of the tube secretes a watery fluid, which is not sweet nor 

 odorous, but which proves quickly fatal to all insects that 

 fall into it. The whole inner surface is covered with very 

 minute prickles, perfectly smooth and pointed downward, 

 which render it impossible for an insect to ascend by walking, 

 even when the leaf is laid nearly horizontal. Within the some- 

 what dilated rim of the tube there is a band ha'f an inch in width, 

 dotted with a sweet secretion, attractive to insects, but not in. 

 toxicating. This also extends downward along the edge of the 

 outer wing to the very ground, thus alluring many creeping 

 insects, and especially ants, to the more dangerous feeding- 

 ground above, where, once losing foothold, it is impossible to 

 regain it. Even flies escape but rarely, the form of the tube and 

 lid seeming to eftectually obstruct their flight. As the result, 

 the tube becomes filled to the depth of some inches with a mass 

 of decaying ants, flies, hornets, and other insects. Within this 

 there is always found a while grub feeding upon the material 

 thus gathered, perhaps the larva of a large fly which has been 

 observed to stand upon the edge of the tube and drop an egg 

 within it. Soon after the full development of the leaf the upper 

 jortion beccmes brovin and shrivelled, which is drre to stdl 

 another larva, the young of a small nio'h, which feeds upon the 

 substance of the leaf, leaving only the outer epidermis, and 

 works its way from above downward till in due lime it spins its 

 cocoon, suspending it by silken threads just above the surface of 

 the insect deiris at the bottom. The whole forms a series of 

 relationships and an instance of contrivance and design, the full 

 purport of which is still by no means fully understood. Oiher 

 species of the genus, as also the allied Darlingtonia of California, 

 manifest the same purpose of insect-capture, whatever the final 

 object may be. 



As complementary to Dr. Mellichamp's paper. Prof. C. V. 

 Riley gave an account of his investigations on the insects more 

 particularly associated with Sarracenia rariolaris, which we shall 

 reprint separately in an early number. 



Number and Distribution of /■'i.ved .Stars is the title of a paper 

 read by Prof. V>. A. Gould, of Cambridge, Mass. The great 

 work of Argelander undertook no less than a complete census of 

 all stars in the northern hemisphere to the ninth m.agnitude 

 inclusive, with as many as possible of the magnitude 9.^. This 

 was successfully executed, and an association comprising the 

 great majority of northern observatories is rrow employing the 

 working list thus obtained for the construction of a catalogue to 

 fix star-places with the utmost attainable accuracy. The magni- 

 tudes are given to the tenth of a unit, from a number of observa- 

 tions on each, in the published catalogue, after having been first 

 estimated by half units. 



Prof. Littrow of Vienna made a careful enumeration of stars 

 for each magnitude, to ascertain whether an approximate uni- 

 formity in the distribution of stars was indicated. If the magni- 

 tudes depend upon distances from us, and the stars are distributed 

 Hith uniformity in space, the number cf stars of any given 

 magnitude should be proportioned to the spherical area within 

 which they are observed. The truth of the hypothesis may be 

 inferred from the degree of accordance between the numbers of 

 star-s of given magnitudes in the catalogue,[and numbers computed 

 from the contents of imaginary spherical shells whose radii 

 would correspond with the respective magnitudes. An approxi- 

 uv. t-; indication might be obtained of tie ri;lative distances of 



