July 15, iSSo] 



NA TURE 



255 



rivers and other bodies of water of the various continents, by 

 Prof. H. Fritz. The author does not think there is any reason 

 for believing that anything lil<e a permanent decrease of the 

 volume of water in rivers has talLen plice, but that this volume 

 is subject to variations, which, when grouped in periods of about 

 ten years, are seen to be wonderfully regular. He gives, for 

 example, the years 1804, 1816, 1S29, 1S37, 1S48, 1860,1871, 

 as years of water maxima, and notes as at least a coincidence 

 that the?e were years of maximum sun-spots. An article by P. 

 F. Bainier refers to the recent discovery of the Niger sources ; 

 there is informa ion on various recent Nile expeditions, and 

 some notes in connection with the projected railway from 

 Mejillones to La Paz in Bolivia. 



ARTIFICIAL DIAMONDS ' 

 T N a preliminary notice, which the Royal Society has done me 

 •*■ the honour of publishing in the Proceedings, I gave a very 

 short sketch of the work I have done which led me to a reaction 

 whereby hard crystalline carbon has been produced. I have 

 now the honour of laying a detailed account of the methods and 

 results before the Society. As far back as September, 1879, I 

 was searching for a solvent for the alkali metals, and tried 

 experiments with many liquids and gases, but invariably found 

 that when the solvent reached the permanently gaseous state 

 chemical action ensued. This was the case even with hydro- 

 carbons, the metal combining with the hydrogen and setting free 

 the carbon. Paraffin spirit, boiling at 75°, was first used in ex- 

 perimenting, and the spirit contained a considerable amaunt of 

 defines ; but even these unsaturated hydrocarbons seemed to be 

 split up in like manner. The experiments were conducted in 

 thick tubes from i to i'5 millims. internal, and 10 to 15 external 

 diameter, and mare of hard glass. 



The alkali metal which decomposes the hydrocarbon retains a 

 quantity of pure hydrogen, %\'hich may be seen by exhausting it 

 by the Sprengel pump. A piece of sodium was exhausted in the 

 molten state for five hours by the Sprengel pump, and when no 

 more hydrogen had been evolved for an hour, a piece was placed 

 in a tube with paraffin spirit and heated for two hours, and when 

 a considerable quantity of carbon was deposited, as much of it 

 was removed as could be conveniently obtained and again 

 exhausted, when 32 times its volume of hydrogen was extracted 

 from it. This was repeated several times, and quantities of 

 hydrogen, varying from 17 to 25 times the volume of the sodium, 

 obtained. Tlie carbou deposited on the tube is of a hard scaly 

 nature, and when the sodium is slowly oxidised and dissolved in 

 water, some very hard scales of carbon are often obtained. This 

 was then the reaction on which my work was built. As potas- 

 sium is a metal of stronger affinities I thought that an examina- 

 tion of its action on paraffin would yield somewhat better results, 

 but in this I was disappointed. Sometimes its action was very 

 great, but it seemed to combine with some of the substance in 

 the tube, and formed black compounds, having no hard carbon 

 amongst them. Some of the experiments did yield a little, but 

 on the whole it was not so good as sodium. Lithium was next 

 tried, and yielded re^^ults which were much more hopeful. 



After an account of experiments on gaseous solution the 

 author proceeds : — The general result obtained from these experi- 

 ments was that the solvent power of w ater was found to be de- 

 termined by two conditions: I. Temperature or molecular vis 

 viva; and 2. Closeness of the mDlecules on pressure, which 

 seems to give penetrative power. From these observations it 

 will be seen that if a bjdy has any solvent action on another and 

 does not act upon it chemically, such solvent action may be inde- 

 finitely increased by indefinitely increasing the temperature and 

 pressure of the solvent. In nature the temperature has been at 

 one time higher than we can obtain artificially, and the pressure 

 obtained by a depth of 200 miles from the surface is greater than 

 can be supported by any of the materials from which we can form 

 vessels. It will thus be seen that, whereas in nature almost 

 unlimited solvent p iwer could be obtained, we are not as yet able 

 to reproduce these conditions artificially. Could pressure alone 

 increase solvent power, then much might be done, but pressure 

 only acts by keeping the molecules close together when they 

 have great vis viva, and this latter is only obtained by high 

 temperature. 



As glass tubes were quite out of the question when a red heat 



' *' On the Artificial Formation of the Diamond." Paper read at ttie 

 Royal Sjciety by J. B. Hannay, F.R.S.E., F.C.S. Abstract by the 

 Auttior. 



and very high pressure were required, iron tubes were resorted 

 to, and a series of attempts made to dissolve carbon by various 

 gaseous solvents. The difficulty of closing iron tubes as com- 

 pared with glass tubes caused me to try various methods, which 

 I shall describe here. Tubes were made of strong hydraulic 

 tubing 20" long, i" thick, and J" bore. These were fitted with 

 a plug, screwed with a strong screw fitting very well. There 

 was placed in the tube some powdered charcoal from which all the 

 inorganic matter had been removed by immersion inhydrocliloric 

 and hydrofluoric acids and washing with water, and then suffi- 

 cient paraffin spirit to fill the tube two-thirds of its volume. The 

 plug was screwed in with a lute composed of silicate of soda and 

 manganese dioxide, but after heating the tube in a reverberatory 

 furnace for four hours it was found to be impossible to remove 

 the plug, so the end had to be bored out. There was neither 

 liquid nor gas in the tube, the luting having leaked. Another 

 tube similarly filled was fitted with a plug with a copper washer, 

 the end of the tube, plug, and washer being polished, but this 

 also leaked, and no result was arrived at. Baryta, clay, asbestos, 

 and other substances wet with silicate of soda, were all tried 

 with the same result — leakage. A silver washer kept compara- 

 tively tight, but only on one occa<ion. It was thus seen that 

 screw-closing would give no reliable results, so another method 

 was tried. A ball of iron, fitting the tube tightly, was placed 

 in it after the materials had been introduced. The end of the 

 tube was then narrowed by compression between rollers and 

 turned smooth inside. The iron ball was then drawn up by a 

 wire attached and luted by silicate of soda and fine manganese 

 dioxide. It was expected that the pressure would only serve to 

 make the closing more secure, but, on heating, the iron yielded, 

 and the ball was driven out with a loud explosion. After trying 

 several other methods of closing — outside screwing and filling 

 the mouth with molten metal on the top of a clay plug being 

 amongst them— I came to the conclusion that nothing wovUd 

 suffice but welding up the open end. This has been, when 

 carried out efficiently, invariably successful, and in all my later 

 experiments I have used it alone. It requires great skill on the 

 part of the workman, and it is only one man in a hundred who 

 can perform the operation with invariable success. The furnace 

 used in these experiments was a reverberatory one, 6 feet long 

 (internal measurement) and 2 feet broad; fire-place, 15 inches; 

 bridge, 9 inches ; hearth, 4 feet. The roof sloped down towards 

 the flue, and the spent gases had exit at the level of the hearth, 

 thus carrying the flame down as it receded from the fire in order 

 to have the hearth of one temperature. 1 he walls were 13 inches 

 thick, and the roof formed of 4-inch fire-clay covers. 



Three tubes, 20" x i" x V' bore, were filled as follows : — _ 



No. I. 3 grms. sodium, \ full paraffin spirit, 

 „ 11. „ ,. * 



„ IIL „ „ f 



On heating them in the reverberatory furnace. No. I. exploded 

 before a visible red-heat had beer obtained, so the temperature 

 was not allowed to rise any higher, and Nos. II. and III. 

 allowed to lie for four hours and then slowly cooled. On being 

 bored open next day, No. II. contained a little scaly carbon, but 

 No. III. contained almost none, and nearly all its liquid had 

 been converted into gas, which rushed out on boring it open. It 

 was noticed by the workmen that the inside of the tube was 

 harder to bare than the outside, and I thought, as I found out 

 afterwards rightly, that the iron had been carbonised and con- 

 verted into steel. It seemed, then, that the free carbon had 

 been taken up by the iron. 



An account of a number of preliminary experiments with 

 various tubes here follows ; — The iron used in making the tubes 

 is what is known as " Lowmoor" iron, a very pure and strong 

 quality, and a portion removed from the interior of a tube which 

 has been used gave, on analysis, 2' 17 per cenL of carbon, 

 showing to what an extent carbonisation had gone on._ 



Having obtained results from this process of a kind which 

 showed that diamond was unlikely to be formed by its agency, I 

 reverted to the original idea of solution of carbon in a gaseous 

 menstruum, and from some experiments I had been carrying^ on 

 with the view- of finding some commercial use for "bone oil," 

 I concluded that the distillate from bone oil containing the nitro- 

 genous bases would be most likely to yield such a solvent. Bone 

 oil, the nitrogenous distillate obtained in the manufacture of bone 

 char, and for a plentiful supply of which I am indebted to Messrs. 

 John Poynter and Sons ^of Glasgow, was distilled, and the 

 portion boiling between 115° and 150° was taken and rectified 



