6o8 



NA TURE 



[April 25, 1895 



times at 164,000 feet (Nature, vol. li. p. 534). If these layers 

 lapered oflF uniformly in eiiher direction Irom the region of 

 maximam deposit, the total mean thickness would be half this, 

 or 82,000 feet ; and if the mean rate of subsidence were never 

 greater than 2"lS feet per century, rhe total time required for 

 the accumulation of Cambrian and post-Cambrian rocks would 

 be not less than 3J millions of years. But there may have been 

 long unknown gaps in the process of their accumulation ; the 

 outer margin of the deposits may have extended far beyond the 

 area of subsidence, and the mean rate of sub>idence may have 

 been at all times considerably less than the upper limit given 

 above. On these accounts, as well as on others that might be 

 mentioned, it seems possible that much more than 3I million 

 years has elapsed since the beginning of the Cambtian 

 period. 



Birmingham, April S. C. Davison. 



The Burmese Chipped Flints Pliocene not Miocene. 



I.v the Geological Magazine for November of last year, p. 

 525, is a review by Prof. T. Rupert Jones, of the important 

 paper, published in the Kaords of the Geological Survey of 

 Itiiiia, by Dr. Fritz Noetling, the Palaeontologist of the Survey, 

 " On the occurrence of Chipped (?) Flinis in the Upper 

 Miocene of Burma." Another paper, by Prof. T. R. Jones, on 

 " Miocene Man in India," appeared in Natural Science for the 

 same month. 



From the fact that the mammals Rhinoceros ferimensis and 

 Hipfarion antelopinum, of which bones were found associated 

 with the flint chips, have only been found in India in Pliocene 

 beds, and from a slight acquaintance, gained, it is true, more 

 than ihirty years ago, with the Burmese strata in which Dr. 

 Noelling's most interesting discovery was maiie, I felt assured 

 that there must be some error in believing that the flint chips 

 occurred in Miocene deposits, and I wrote to Dr. Noetling on 

 the subject. I have just heard from him in reply. In a letter 

 from Upper Burma of .March 11, he tells me he has now defi- 

 nitely ascertained that the bed containing the chipped flints is 

 Pliocene. 



Further particulars will, I hope, be published before long by 

 Dr. Noetling ; and I should not have written on the subject but 

 that a serious error is caused by its being supposed that 

 " .Miocene Man " has been shown to have exi^led in India, and 

 it is desirable that this error should be corrected without delay. 

 The importance of the discovery is in no way diminished by 

 the correction of the geological date to which the flint-bearing 

 stratum is referred. W. T. IJlanford. 



April 17. 



The Mandrake. 



With regard to Prof. Veth's exhaustive account of the 

 mandrake (referred to in Nature of April 11, p. S73)> 

 it may be useful to students of folklore to call iheir 

 attention to the occurrence in the Chinese literature 

 of a similar superstition, wherein Phytolacca acinosa (Shang- 

 luh) takes the place of Mandragora officimirum. Sie 

 Tsai-Kang's " Wu-tsah-tsu," written about 1610 (Japanese 

 edition, 1661, tome x. p. 41), contains the following passage : — 

 " The Shang-luh grows on the ground beneath which dead man 

 lies ; hence its root is mostly shaped like a man.' ... In a 

 calm night when nobody is about, the collector, offering the 

 owl's flesh roasted with oil, propitiates the spirit of the plant 

 until /^nwya/uj crowd about the latter; then the root is dug 

 out, brought home and prepared with magic paper for a week ; 

 thus it is made capable of speech. This plant is surnamcd 

 ' Ye-hu ' (1.^. Night Cry) on account of its demoniacal nature. -' 

 There are two varieties of it : the while one is used for medi- 

 cine ; the red one commands evil spirits, and kills men when it 

 is internally taken by error." Kumagusu Minakata. 



April 16. 



I Here the author sayt; "It \% popularly called * ChanK-liu-Kan ' 

 (= Witch-trrr-ront)." The name »hows that the root wa* used in witch- 



Tafl, 



j'.r !i.i l'nl;*rir.i..a, 

 the Chinese name 



rhal of the Mandragora (r/ Hone, "The Year- Book," 

 ■|. 



tion tuKKeiitcd for this name is that, as long as the fruit 

 mains unripe, the cuckoo continues 10 cry every night 

 •■u^r.). However, seeing thai the belief in the shrieks 

 ' -vas once current among the Kuropeans (" Encyclo- 

 ' Qth ed. vol. xv. p. 476), it would be more just to derive 

 Night Cry" from an analogous origin. 



A Claim for Priority. 



I SEND you, under ,'eparate cover, a copy of an address, 

 " Radiant Matter," &c. , delivered at the International Electrical 

 Exhibition, held in Philadelphia in 1SS4, reprinted from the 

 Journal oi \\\e Franklin Institute, September 1SS5. and would 

 call your attention to thede'Cription of the method of preparing 

 films of gold and other metals of extreme thinnes<, far exceed- 

 ing in tenuity those described in Nature as novelties in 

 metallurgical methods (prepared in identically the same manner), 

 and exhibited at a conversazione of the Riyal Society, June 13, 

 1894. The first published note regardin;» this subject may be 

 found in the Proceedings oi \.\\t .Vmeric:in Phil. Siic, vol. xcix. 

 February 16, 1S77. Later and fuller notices will be 

 found in fourn. Franklin /ntliluU, April 1877, June 1S77, 

 September 1SS5, and September 1894. In addition to the 

 above, the process was fully described in U.S. Patent, 19S, 209, 

 December 18, 1S77. Alex. E. Outerbkidge. 



Philadelphia, April 5. 



NO. 1330, VOL. 51] 



I 



AN IMPROVED METHOD FOR THE MICRO- 

 SCOPIC INVESTIGATIOX OF CRYSTALS. 



A MEMOIR of consider.ible importance to all who 

 -'*• are interested in the microscopic determination of 

 the characters of crystals, is contributed by Prof. Klein 

 to the Sitzungsberichte of the Berlin Akadcinic der 

 IVtsse/isc/tafU/i (or ]3.nu:iTy ji, 1895 The two essential 

 points of the communication are that a form of stage 

 goniometer is described, which permits of the most com- 

 plete examination of many of the principal zones of the 

 crystal with one and the same setting of the crystal upon 

 its holder, and that the crystal is immersed during the 

 observations in a liquid whose refractive index is about 

 the mean of the refractive indices of the crystal. The 

 idea of the " Universaldrehapparat," as the new stage 

 goniometer is termed, appears to have suggested itself 

 almost simultaneously to Prof. Klein and to Herr von 

 Federow, for the former described an earlier form of it 

 in the Silcunx.iitri'c/ili: of April 1891, while the latter 

 published a description of an " Universaltischen" for 

 the mictoscope in the Zcitschrift fiir h'rystallns^rapftie 

 of May in the same year. Herr von Federow had pre- 

 viously contributed to the Zcitschrift a remarkable 

 memoir concerning a theodolitic universal goniometer, 

 and the application of the principle of that instrument 

 to the microscope goniometer followed naturally there- 

 from. The present memoir of Prof. Klein affords so 

 admirable a description of the improved instrument, 

 which has been constructed for him by the well-known 

 Berlin crystallographical optician, Herr Fuess, and like- 

 wise of the mode of employing it in connection with the 

 immersion method, that readers of N.VTUKi-; may find a 

 brief account of it not uninteresting. I'nfortunately this 

 description cannot well be illustrated, as I'rof. Klein's 

 illustrations are photographic reproductions which are 

 unsuitable for further reproduction. 



The microscope should of course be one of the petro- 

 logical type, fitted with the usual accessories for the 

 examination of crystals in parallel and convergent 

 polarised light. The particular instrument constructed 

 for Prof. Klein is somewhat similar to the largest Fuess 

 model. It is so arranged with respect to the centre of 

 gravity that it can be rotated into the horizontal position 

 whenever desired, a point of some importance with 

 regard to the use of an immersion litpiid. The stage is 

 of course circular, and is divided so as to read with the 

 aid of a pair of verniers to single minutes ; it is further 

 provided above with two graduated rectangular traversing 

 movements, one of which is supplied with a micrometer 

 registering 001 m.m., while the other is capable of much 

 more rapid motion. The advantages of the simultaneous 

 rotation of the polarising and analysing nicols, as adopted 

 in the microscopes made by Mr. Swift under thedirection 

 of Mr. Allan Uick, have been so well appreciated by 



