558 



NA TURE 



[Al'KlL 13, 1899 



and Archdeacon Maples (he was then), both of whom had 

 travelled a good deal in Africa — Maples more especially — and 

 had seen something of the habits of lions. 



Bishop Smythies defended the former theory ; Archdeacon 

 Maples — a most talented and entertaining man — the latter, say- 

 ing he had known instances of lions killing [lorcupines, and 

 adding that he believed the porcupine to he specially endowed 

 with the power to propel his quills into his assailant when so 

 attacked. 



At this juncture, Bishop Smythies generally lost patience and 

 declined to continue the argument. 



Had Bishop Smythies lived, it would have interested him, as 

 it may interest some of Nature's readers, to know that in 

 March la.st, at the Salt Stream, two days' march N.\V.,of 

 Kibwezi, I shot a fine old lion in whose left fore-paw were 

 deeply buried the tips of three porcupine quills. 



These are in my possession at the present time : the longest 

 measures exactly i inch ; another is almost as long, and measures 

 \% of an inch. How long he had been afflicted with these 

 painful appendages I could not say — months at any rate, or 

 may be years ; since the paw was not inflamed, and from con- 

 stant friction and pressure in using it the cartilage surrounding 

 the quills had become callous. 



There is no immediate reason for supposing that in this case 

 the lion killed the porcupine acting on the impulse of inordinate 

 hunger : the Salt Stream country teems with game — such as 

 rhinoceros, zebra, hartebeeste, gnu, gazelles, and ostriches ; it 

 is also just such a country for cover as lions habitually frequent, 

 and do frequent in numbers, as may be judged from the fact that 

 in two days I saw them on three occasions. 



Leopards, I was already aware, prey freely on porcupines. 

 But this is the first instance which has occurred — in my own 

 experience — of a lion's doing so. RlCH.^RD Crawsh.w. 



Neugia, Kitwi, British East Africa, February 6. 



Precipitation of Gold by Charcoal. 



Ix your " Notes " this week, the use of charcoal as a pre- 

 cipitant for gold from solutions is mentioned as being pretty 

 largely applied in -Australia, and that the cause of precipitation 

 is not understood. 



I venture to put it this way : that by some process, accel- 

 erated no doubt by surrounding physical changes, there is 

 formed within the charcoal carbon w««oxide (and also carbon 

 dioxide), which is a precipitant for gold. The difficulty of 

 ridding charcoal of oxygen without chemical combination is 

 well known. 



I may mention that I am now using carbon monoxide as an 

 industrial precipitating agent in gold-winning. 



James C. Richardson. 



19 Claremont Square, London, March 29. 



It is an old idea that carbon monoxide is the real agent in 

 the precipitation of gold from solutions of the chloride by 

 means of charcoal. An objection to Mr. Richardson's sugges- 

 tion, that the same view may be taken in the case of cyanide 

 solutions, lies in the fact that, according to my own experi- 

 ments, carbon monoxide does not appear to precipitate gold 

 under ordinary conditions from these solutions. 



The main objection, however, to all the theories put forward 

 to account for the precipitation of gold by charcoal is that they 

 are not supported by the results of any published experiments. 

 TiiK Writer hi- the Note. 



Instincts of Wasps. 



PerhaI'S it may interest your reviewer of Dr. and Mrs. 

 Peckham's work " <Jn the Instincts and Habits of the Solitary 

 Wasps," to learn that one of the main results in question has 

 been already arrived at in a paper by the late Prof. SchitT, of 

 Geneva, in MJmoires tie la Sac. dc Physitjue it d' Histoire 

 naUirelle dc Geneve, vol. xxviii., 1882-3. I quote the following 

 passage, as in some way complementary to the observations of 

 Dr. Peckham : 



" D'ailleurs, unexamen microscopique approfondi du systeme, 

 ncrveux des animaux intoxiques par les guepes n'a pas revcle la 

 moindre lesion dans les nerfs et les ganglions <le ces animaux." 



Freiburg, Badcnia, March 18. Uaviii Wktti-rhan. 



NO. T537. VOL. 59] 



CORUNDUM AND ITS USES} 



'T*HE three works cited below give much new and 

 -'■ valuable information concerning the mode of occur- 

 rence, the processes of mining, and the uses of corundum. 

 As the mineral is of growing economic value, and is 

 every day finding fresh applications in the arts, it seems 

 desirable to call attention to some of the facts which are 

 for the first time made accessible to the public in these 

 works. We may exclude from view, for our present 

 purposes, the clear and brightly coloured varieties of 

 corundum, so much priced as gem-stones (ruby, sapphire, 

 &c.), and also the composite material known as emery. 

 The latter substance should be regarded not as a mineral, 

 but as a rock — one in which the mineral corundum is a 

 predominant constituent, though always mi.xed with 

 magnetite, tourmaline, and many other minerals. 



Among the works of which the titles are given below, 

 precedence may be fairly conceded to that which deals 

 with Indian corundum. Corundum is a distinctively Indian 

 mineral : its name is of Indian origin, and its recognition 

 as a distinct mineral species w as the result of the study of 

 Indian specimens. The plan, now adopted by the Director 

 of the Geological Survey of India, of republishing the 

 "Manual of Economic Geology" in a series of sejjarate 

 memoirs, each dealing with a particular mineral, or group 

 of minerals, is one which must commend itself to every 

 one as being calculated to furnish us with the most com- 

 plete and exact information from the pens of the best 

 qualified authorities. It is fortunate that the writing of 

 the memoir on corundum has fallen into the hands of so 

 competent a mineralogist and geologist as Mr. Holland. 



The first nine pages of the memoir are devoted to a 

 condensed, but very clear and e.\act, account of the 

 mineralogical characters of corundum. The next ten 

 pages contain an admirable discussion of the geological 

 relations of corundum. Mr. Holland's studies of the 

 famous corundum-yielding rocks of Southern India have 

 furnished him with much fresh material bearing on 

 the mode of oc currence and association of the mineral. 

 In the work before us only a brief sketch can be given of 

 these, and of the theoretical questions upon which they 

 throw much new light. It is to be hoped that the present 

 short memoir will be followed by detailed accounts of 

 the geology of Salem and other districts in Southern India, 

 where Mr. Holland and several of his colleagues have 

 had the opportunity of re-examining the rocks made 

 known to us by the travels of Leschenault de la Tour, 

 and the petrographical researches of Prof Lacroix. 



The larger portion of the memoir is occupied by 

 detailed accounts of the exact distribution of corundum 

 throughout the Indian Empire, and a discussion of the 

 uses of corundum. In this latter part of the work much 

 valuable information, carefully collected from a number 

 of trustworthy sources, has been brought together ; and 

 the reader cannot fail to find much that is new, and 

 also has important bearings on the economic uses and 

 the manufacture of the various varieties of corundum as 

 known in the markets of the world. 



While the corundum of India has been sought for 

 from the earliest times for use in grinding gems, and 

 other purposes in which abrasive materials of the greatest 

 hardness are required, the rich deposits of the same 

 mineral in the Eastern United States have only been 

 worked for similar purposes during the last twenty 

 years. 



' "A Mami.il of ihc GcoloRyoflndi*.— Economic Geology.' Bythebtr 

 Prof. V. Ball, C U. I.L.D., F.R.S. Second edition revised in p.Tri~ 

 Piirt I. Corundum. Hy T. H. Holland, .VR.C.S., F.G.S. (CalcuU.i, 

 1808.) 



'' Minei.il Risuurces of ihe Uniled Slates ; Sevenleenlh Annual Rcpon 

 of the U,S. tleolonical Survey ; Corundum Deposits of the Southern 

 Appal.lchi.inRiEii.ns.- By J. A. Holmes. (WashinKlon, D.C. 1806.) 



"Economic t„-..l..Ky of h.islern Ont.irio : Corundum and other 

 Minerals." Ily Willct (1. Miller. Report of the Bureau of Mines. Vol. 

 vii. PI. J. (Toronlo, 1896.) 



