AND OF THE PHYSICAL SCIENCES. 



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grew softer. Since that period, however, various chemists have burned Diamonds 

 with as much facility as a piece of iron, wire, or wood, by exposing them on a piece 

 of charcoal placed in the flame of a common lamp, or even a candle, and blown with 

 a. current of oxygen gas. At a heat less than the melting point of silver, it gradually 

 dissipates, burns, and combines with nearly the same quantity of oxygen, and forms 

 the same quantity of carbonic acid as charcoal. 



Dr Murray of Edinburgh has invented the most simple apparatus which we have seen 

 for exhibiting the combustion of the Diamond. The annexed cut gives a representa- 

 tion of it. A glass globe is filled with oxygen obtained from 

 oxymuriate of potassa over mercury. A portion of the stem of a 

 tobacco pipe, attached to the curved end of a wire fastened to the 

 cork above, carries the Diamond, fixed in a nidus prepared for it. 

 The Diamond is kindled by the oxy-hydrogen blow-pipe, or a 

 stream of oxygen urged over the flame of a spirit-of-wine lamp, 

 and then conveyed into the globe. When the combustion of the 

 Diamond ceases, lime water is passed over the recipient, and the 

 weio-ht of the carbonate of lime formed and precipitated, indicates the quantity of 

 Diamond consumed. Dr Clark exposed a Diamond of six carats, of an amber colour, 

 to the flame of the gas blow-pipe. It became colourless and transparent — after this 

 it became white, and by continuing the heat, it was entirely volatihzed in about three 

 minutes. It has also been ascertained by Guyton, Davy, and others, that although 

 Diamonds, whether Oriental or Occidental, are the hardest of aU substances, they 

 yet contain nothing more than pure charcoal or carbon. The extreme hardness and 

 transparency of this carbon furnish a problem which has hitherto baffled the efforts 

 of philosophers to solve satisfactorily. Nevertheless, the knowledge of the inflam- 

 mability of Diamonds has very considerably reduced their mercantile value, and will 

 probably bring it, like that of all other articles, to the common standard of com- 

 parative use. 



Diamonds were first brought to Europe from the East Indies, where they are 

 found in various parts. The first mine known there is that of Sumbulpour on the 

 river Goual, which falls into the Ganges. A chain of mountains extending from 

 Cape Comorin to Bengal are the most celebrated for producing Diamonds. But the 

 chief of these are in the kingdom of Golconda, furnishing the greatest quantity and 

 most esteemed Diamonds, especially those of Pastall, which are sent to Calcutta, where 

 they are sorted, sealed up in bags, and conveyed to London. In 1770, there were 

 fifty Diamond workings in the kingdom of Visapour ; these furnished more than thoso 

 of Golconda, but were abandoned, being smaller. They are also found in the Island 

 of Borneo. The total annual value of the Diamonds so collected is said to amount to 

 about L. 142,500, exclusive of thoso which are smuggled. The largest Diamond 

 which has hitherto been found, is that called the IMattan Diamond, from Borneo, and 

 particularly described at page 31 of this Journal. The nest largest Oriental Diamond 

 is one, the size of a pigeon's egg, of the weight of 193 carats, equal to about one 

 ounce two pennyweights Troy. The Empress Catharine II. of Russia offered 

 L. 104, 166, 13s. 4d. besides an annuity for life of L.1C41, 13s. 6d., which was re- 

 fused; but was afterwards sold to Catharine's favourite, Count OrlofF, for the above 

 sum without the annuity, who presented it to the Empress on her birth-day, in 

 1772. This gem exceeds the famous Pitt Diamond in size, and is reckoned equal in 

 water. It is now in the sceptre of Russia, and is considered the finest of the kind in 

 Europe. The late Queen of Portugal possessed the next largest Diamond in Europe, 

 but we are not aware whether it is still in the family. The Pitt Diamond weighs 

 136 carats, or nearly an ounce, it was purchased for 2,500,000 livres, and is now the 

 finest of the crown jew^els of France. 



Brazil Diamonds.^ln the year 1728 it was discovered that Diamonds were to be 

 met with in some branches of the river Das Caravilas, at a considerable elevation, 

 and at Serro de Trio, in the province of Mino Geracs, in the Brazils, belonging to 

 Portugal. The Rio de Janeiro fleet brought home at once 1 146 ounces of them. Such 

 a considerable supply would have reduced the value of Diamonds, had not the 

 Government of Portugal laid restrictions on the persons who searched for them. 

 The Diamonds are found in such rivers, the courses of which have been more or 

 less altered ; and it seems probable that they are washed down by the torrents from 

 the mountains, as they are found in the greatest plenty after violent storms of raitu 

 They are not, however, confined to the beds of rivers alone, as they have been found 

 in cavities and water-courses on some of the highest mountains in the district. The 

 principal work in the present day is at Mandanga, or the Jigitonhona, a very shallow 

 river, which admits of its waters being dammed out, or diverted from their 

 course. 



We learn from IMawe's Travels in the Interior of Brazil, that the Diamond mines 

 of that country are situated due north of the mouth of the Rio de Janeiro. The capital 

 of the district is called Tjuco. The face of the country exhibits in all directions a 

 series of gritstone rocks alternating with micaceous schislus^ in which numerous 

 rounded quartzose pebbles are embedded, giving the whole the appearance of plum- 

 pudding stone. 



In the splendid collection of I\Ir Hewland, there is a Brazilian Diamond embedded 

 in brown iron ore ; another, also, in the same substance, is in the possession of M. 

 Schuch, at Lisbon. Eschwege has, in his own Cabinet, a mass of brown iron ore, in 

 which there is a Diamond in a drusy cavity of a green mineral, conjectured to be 

 arseniate of iron. From these facts he infers that the matrix of Brazil Diamond is 

 brown iron ore. The crust which envelopes the rough Diamond is found thicker on 

 those from Brazil than those from the East Indies, and hence they are easily distin- 

 guished in their natural state ; but as the most skilful lapidaries may be deceived in 

 them afttrr they are cut, they are accordingly of equal value in trade. This equa- 

 lity, however, is only to be understood as relating to small ones, as most of the 

 Occidental Diamonds beyond four or five carats have blemishes, which are seldom 

 found in the Oriental, and in that case the difi'erence is great. Some IMineralogists 

 are of opinion that the latter are harder and more brilliant than the former ; but 

 this opinion is not sanctioned by experiment. 



North American Diamonds. — A Diamond weighing one carat and a half was 

 found in the autumn of 1835 in the washings of a stream in North Carolina. 



Russian Diamond ilfmes.^When, in the year 1626, Professor Engelhardt 

 undertook a scientific journey into the Urahan Mountains, he remarked that the 

 sands in the neighbom-hood of Kouspra, and those of the Platina mines at Nigny- 

 Toura, strikingly resemble the Brazilian sands in which Diamonds are found. Baron 

 Humboldt, during his residence in that country in 1830, confirmed this resemblance ( 

 and examinations having been made according to his advice, a young countryman who 

 was employed in washing the auriferous sand, on the grounds of the Countess Poher, 

 discovered a Diamond on the 20th June 1830, which was nothing inferior to those 

 of Brazil ; soon after many others were found superior in weight to the first. Thus 

 Russia has added this source of riches to those of which of late years it has obtained 

 in the form of Gold and Platina Mines, from the Ural chain of mountains ; and has 

 proved, that what has hitherto been supposed to be the case is not correct, that 

 Diamonds were only found near the line, and none beyond the tropics. 



Professor Jameson is of opinion, that Diamonds continue to be formed even at the 

 present day in some alluvial districts of India ; as they have been discovered in alluvial 

 beds of clay, not as a secondary deposit, but as an original one ; and, says he, ** no- 

 thing more seems necessary for the formation of the Diamond in such situations, than 

 time, or other favorable circumstances, for allowing portions of the carbonaceous 

 matter in the soil to be reduced to the adamantine state, and afterwards to coalesce, 

 according to the laws of a£5nity, into the granular and crystallised form — in short, 

 to form Diamond." The Professor also promulgates another theory for the forma- 

 tion of Diamonds ; he says, ** a direct appeal to the characters of some woods seems 

 to countenance the idea I some years ago suggested to the Wcrnerian Society, 

 that vegetables may contain carbonaceous matter approaching to the adamantine state. 

 Certain woods which have not the gritty feel of those that contain silica are uncom- 

 monly hard, dark coloured, and take a high polish ; these, I conjecture, may be some- 

 what of the adamantine nature. If this should prove to be the case, it would neither 

 be surprising nor unexpected, that such trees may secrete carbon in the adamantine 

 state, v."hich, on being removed from the influence of the living principle of the plant, 

 would, by the power of affinity, form into true Diamonds, just as the silica secreted 

 from the Bamboo takes the form of opal, and that from teak wood the characters 

 of homstones." 



In support of Professor Jameson's theory, we may mention that Dr Hamilton was 

 informed by the workmen, when he visited the Diamond Mines of Parma, in Bengal, 

 that the generation of Diamonds was always going forward, and that they had as 

 much chance of success in searching earth that had been fourteen or fifteen years 

 unexamined, as in digging what had never been disturbed; and, in fact, he saw them 

 digging up earth which had evidently been before examined, as it was lying in irre- 

 gular heaps as thrown out after examination. These men are so expert at discover- 

 ing Diamonds, that they never overlook any during their search. 



Sir David Brewster states, that Dr Voysey has shown that the matrix of the 

 Diamonds produced in Southern India is the sandstone breccia of the dog slate 

 formation; and that Captain Franklin has found, that in Bundel Kund, the rocky 

 matrix of the Diamond is situated in sandstone, which he imagines to be the same as 

 the new red sandstone of England ; that there are at least four hundred feet of that 

 rock below the lowest Diamond beds, and that there are strong indications of coal 

 underlying the whole mass. Sir D. Brewster, from certain cavities observed in 

 Diamond, and from their cfl"ect3 in polarizing light, is led to conjecture, " that the 

 Diamond originates, like amber, from the consolidation of perhaps vegetable matter, 

 which gradually acquires a crystalline form from the influence of time, and the slow 

 action of corpuscular forces." 



The usual method of seeking Diamonds is by throwing the stones and rubbish with 

 which they are supposed to be associated into a cistern, full of water, having a cock 

 and plug at the bottom. The lumps are then broken, and the muddy water drawn 

 off till the stones are washed clean. When the sun shines bright, the sand and 

 stones which remain in the cistern arc carefully examined. In this business the work- 

 men are so expert, that the smallest crystal cannot escape them. 



The cutting and polishing of Diamonds are performed by first cleaving them in 

 the direction of their lamells, and then rubbing them against each other, and the 

 powder or dust thus disengaged serves to grind and polish them ; these latter opera- 

 tions are performed by the aid of a mill, which turns a wheel of soft iron, sprinkled 

 over with Diamond-dust, mixed with olive oil. Tlie same dust, well ground and 

 diluted with water and vinegar, is used for sawing Diamonds, which is efl'ected by 

 means of an iron or brass wire as fine as a hair. 



GEOLOGY. 



On the Excavation of Valleys. — There is much diversity of opinion among 

 Geologists on the subject of the excavation of valleys, and of the effects produced by 

 river currents in modifying the form of the solid parts of the earth; and several 

 distinguished men have lately turned their attention to this important and interesting 

 subject. Professor Sedgwick seems to have formed opinions on this subject, which 

 approach near to the true theory. Messrs Lyell and IMurchison discussed this sub- 

 ject in a Memoir on certain portions of the volcanic regions of Central France. 

 Their opinions accord with the views of I^Iontrosier, Scrope, and some other writers, 

 who conceive that the existing rivers have, by a long continued erosion, eaten out 

 deep gorges, not only through currents of basaltic lava, which have flowed through 

 the existing valleys, but also through solid rocks of subjacent gneiss. They further 

 seem to prove, that no great denuding wave or mass of water, lifted by supernatural 

 force above its ordinary level, could have assisted in forming such denudations ; for 

 the country is still studded with domes of incoherent matter, the remnants of former 

 craters, from which may be traced continuously streams of lava, intersected in the 

 course of the rivers by these deep gorges — the gauges and tests of the erosive power 

 of running water during times comparatively recent. 



Mr Conybeare proves that, within the records of history, the river Thames has had 

 no erosive power on the valley, nor produced any effect on the general features of 

 the country through which it flows, and that the propelhng force of its waters is not 

 now, and never could have been, adeqxiate to the transport of the boulder stones. 



