478 



♦ KNO^A/LEDGE ♦ 



[June 5, 1885. 



remote geological eras. I have in my possession shark's 

 teeth collected in the ninhbourhood of Charleston, S.C., 

 which are 5 J in. long by 4}, in. broad, and in the Museum 

 of Charleston they have shark's teeth much larger even 

 that that. 



The largest calamaries of the present time are certainly 

 larger than any of those whose remains exist as fossils. 

 A cuttle thrown up on the shore of Newfoundland was 

 80 ft. long. 



On the whole, it may be doubted whether at any time 

 in the past history of the earth the average size of the ten 

 largest creatures by sea and land exceeded the average size 

 of the ten largest species existing at the present day. — 

 Newcastle Weekly Chronicle. 



THE OEIGIX AXD HOME OF THE 



DIAMOND. 



Bt W. Jerome Hareisok, F.G.S. 



THE DIAilOXD I^" SOUTH AFRICA. 

 (Contimiei from pwje 439.) 



THE difficulty of transport has been a great drawback 

 to the success of the diamond-mines grouped round 

 Kimberley, the nearest railway — from Port Elizalieth to 

 Bloemfontein — being 200 miles distant, and all traffic being 

 conducted over the heavy sandy soil by bullock-wagons 

 and (for passengers) a ten-horse coach. For this reason 

 the price of coal at the diamond-mines has averaged £1.5 

 per ton. But in November last a new line connecting 

 Cape Town with the Orange River was completed, from 

 which Kimberley is distant only 74 miles. Another 

 point of interest is that the new gold-fields of the Trans- 

 vaal lie about 500 miles north-east of Kimberley, on the 

 slopes of the Drakensberg Mountains, where the Vaal 

 rises, and from which the diamonds found in the river- 

 gravels were at one time thought to be derived. 



ORIGIN OF THE DIAMOXD. 

 Perhaps it will be best to first state briefly two or three 

 of the various theories which have been advanced : — 



1. Sir A. 0. Ptamsay has urged that the real home of 

 the diamond is in the schistose or gneissic rocks, of high 

 antiquity, which are known to underlie the Kimberley 

 shales, and which in other regions are even more directly 

 associated with diamonds. From the broken and imperfect 

 state in which the diamonds of South Africa are fre- 

 quently found, it is certain that they cannot have been 

 formed in the exact situation in which we now find them, 

 while the fragments of gneiss which also occur in the mines 

 prove that the diamond-rock must have passed upward 

 through the gneiss. 



2. Professor H. G. Seeley has suggested that carbonic 

 arid found its way downward together with the water 

 which (after its conversion into steam) has been shown to 

 be the priucipal cause of volcanic eruptions. The carbonic 

 acid was decomposed by heat, and then, under great 

 pressure, the liberated atoms of carbon built up the 

 crystalline form of that element known as the diamond. 



3. Reasoning from the experiments of Mr. Hannay, it 

 seems not impossible that the diamonds may have been 

 derived from the carbonaceous matter contained in the 

 shales through which the diamond-rock passes. Xot from 

 those shales which form the walls of the present mines, 

 but from shales occurring at a greater depth, and through 

 which the intrusive bronzite has pre^-iously passed. If 

 this be the ease, it is clear that the supply of diamonds 



will cease when the shales have all been worked through. 

 In any case, the deepening of the mine will shed light 

 upon the problem. Under the great pressure and high 

 temperature to which the hydro-carbons in the shales would 

 certainly be subjected at the time of the outbreak by which 

 the existing pipes of volcanic rock near Kimberley were 

 formed, the hydrogen of these hydro-carbons would be 

 strongly attracted by the metal magnesium which now 

 forms part of the bronzite. The carbon atoms — set free in 

 this way — under the enormous pressure to which the whole 

 mass would then be subjected, might aggi-egate together to 

 form diamonds. 



In any case, it is impossible not to agree with Professor 

 X. S. Maskelyne when he says : " It is possible that carbon, 

 like metallic arsenic, passes directly from the state of a 

 solid into that of a vapour ; and that the condition for its 

 sublimation in the form of crystals, or its cooling into the 

 crystal diamond, is one involving a combination of high 

 temperature and high pressure present in the depths of the 

 earth's crust, but very difficult to establish in a laboratory 

 experiment.'' 



Although, in the future, the geologist and the chemist 

 must work together in the interesting task of discovering 

 the mode of genesis of the diamond, yet it is clear that 

 the onus of the direct proof must lie with the latter. In 

 years to come, when the rocks of the diamantiferoua 

 regions shall have been mapped and studied as accurately 

 and thoroughly as those of England have been, the geologist 

 will probably be able to accurately locate the diamond in 

 its true home — in the rock in which it was produced. But 

 as to the mode of its origin in that rock, the chemist will 

 have much to say ; nor will the proof be coDsidered 

 complete until diamonds are produced artificially with 

 certainty and ease. That they will be so produced the 

 writer of this article considers certain, and if chemists had 

 been able to command the expensive appliances necessary 

 for the performance of the many and intricate preliminary 

 experiments required — experiments which may involve 

 years of failure — it is probable that success would have 

 been attaiced ere now. When the Edison of Chemistry 

 arrives, artificial diamonds will be successfully made ; they 

 will, perhaps, not be so ornamental as those occurring 

 naturally, but there is a wide field of usefulness awaiting 

 such a product in the arts and manufactures. 



Society of Arts. — The results of the Society of Arts' eiamina- 

 tions have jnst been published. There was a satisfactory increase 

 in the number of candidates, 1,20S having presented themselves at 

 •14 centres ; whereas last year there were 901 candidates and 3S 

 centres. Of these 1,20b candidates 953 passed and 255 failed. The 

 number of papers worked was 1,321 ; of these 145 took first-class 

 certificates, 410 second-class, and 474 third-class, while to 292 

 papers no certificate was awarded. Eleven of the thirteen subjects 

 set down for examination were taken up. In two no examination 

 was held, as the requisite number of candidates (25) did not pre- 

 sent themselves. The largest number of papers worked (336) was 

 in book-keeping. Other favourite subjects were : — Arithmetic, 

 171 ; Enirlish (including composition and correspondence and precis 

 writing), 118 ; shorthand, 253 ; theory of music, 243. In French 

 there were 06 candidates ; in German only 28. 



EEEATi. — Delete "such" in column two, p. 462, line two from 

 the bottom. In the review of the " Revised Version of the Bible," 

 p. 463, second line, for "English-spoken races," read "English- 

 speaking races." In " Letters Received and Short Answers," p. 467, 

 in the reply to General Babbage, the concluding sentence should 

 run: — "If the expenditure of £17,000 of the national fnnda had 

 had no other result than the publication of the chapter on ' In- 

 trigues of Science,' in the work quoted by General Babbage, it 

 would have been deplorable." The name of the maker of the 

 Tandem tricycle, commended by Mr. Browning in letter 1720 

 (p. 445), should be " Leni," and not " Levi," as there printed. At 

 page 467, column two, in reply to " X.Y.Z.," for " Webb's Series" 

 read " Weale's Series." In the editorial note to Letter Xo. 1,727, 

 page 466, "eye-pieces" should be "eye-piece." 



