256 



NA TURE 



\_7nly 15, iSSo 



over solid caustic potash, and latterly over sodium. When satis- 

 fied that it was free from moisture, oxygen, and sulphur, a tube, 

 2|" X 20" X i" bore, was three parts filled, and some charcoal 

 powder added^ and the whole welded up solid. I found that 

 the nitrogenous liquid was even worse to work with than the 

 hydrocarbon, as on coming into contact w'ith the hot iron it 

 burnt it away at once, and as the tube was of great diameter it 

 was extremely difficult to keep the lower part cool. For welding 

 it had to be arranged so that it was standing in a tub of ice, and the 

 top projecting through the bottom of the forge, and heated until 

 it was at a welding heat, with as little de'ay as possible. When a 

 tube was obtained welded up solid it was heated to a dull red-heat 

 for 14 hours and allowed to cool ; on opening the tube there was a 

 very great out-rush of gas, and the carbon was to a certain extent 

 dissolved, and some minute portions of it very hard. Still, under 

 the microscope it presented little difference in appearance from 

 the wood charcoal employed, some of the features, however, 

 being obliterated, and it had a bright appearance. Another 

 tube of the same dimensions and contents was closed up in the 

 same manner, but after eight hours' heating it burst with a loud 

 explosion. I had noticed that a tube which had been once used 

 and been partially carbonised woidd not stand a second heating, 

 and for this reason I had no belief in the power of cast-iron or 

 steel to withstand the great pressure at a red heat. Nevertheless, 

 as many of my friends had urged upon me to try these materials, 

 I had a cast-iron tube made, 3j" X 24" X i" bore, and filled 

 two-thirds of its volume with bone oil distillate and carbon, and 

 then welded up. We succeeded after a little trouble in making 

 a good weld, and the tube was then slowly raised to a dull red- 

 heat in the furnace. It had not been heated for more than an 

 hour when it exploded with a great noise and knocked down the 

 back and one of the ends of the furnace, leaving the %vhole 

 structure a wreck. The tube had broken into small fragments, 

 and was quite unlike the malleable iron tubes which generally 

 tore up. Thinking that it was perhaps a bad casting, I tried 

 another, but it leaked all over, and emptied itself before the 

 temperature was nearly up. A third tube of the same material 

 burst like the first, but as I had built up the furnace with large 

 blast-furnace blocks, it was not blown down. Cast-iron being 

 inadmissible, experiments were then made with steel. I had 

 several tubes made of this material by the best firms in the 

 kingdom — made by the three methods, Bessemer, Siemens, and 

 the crucible method — but they had the same faults as cast-iron, 

 although to a less degree. The difficulty in making a good weld 

 in cast-iron and steel tubes makes their employment in such 

 experiments as these a matter of inconvenience. Out of five 

 tubes made of steel, some of which were made of the very 

 toughest material manufactured by Messrs. Cammell and Co., 

 only one held in the substance completely. Three burst in the 

 furnace, and one had leaked by its porosity. The top of the 

 furnace, by the continued shocks of explosions, fell in at the 

 bursting of the last of the steel tubes. The continued strain on 

 the nerves, watching the temperature of the furnace, and in a 

 state of tension in case of an explosion, induces a nervous state 

 which is extremely weakening, and when the explosion occurs it 

 sometimes shakes one so severely that sickness supervenes. An 

 account of several experiments follows, none of which were, 

 however, successful. 



I thought I should either have to abandontheattempt or begin 

 experiments of a very expensive nature, using large tubes and a 

 large furnace, as 20-inch tubes of a greater diameter than four 

 inches could net be closed when three parts filled— at least by 

 welding. As some of them, however, seemed to stand, I deter- 

 mined to make some further trials with the apparatus I had at my 

 disposal ; so another tube, 20 " X 4" X J" bore was filled, using 

 4 grras. of lithium and a mixture of bone oil, carefully rectified, 

 90 per cent., and paraffin spirit 10 per cent., using these propor- 

 tions because I had never had any results with a high percentage 

 of bone oil, the tubes so filled having burst. The tube was closed 

 with great difficulty, being three-parts full of liquid, and then 

 heated to a visible red heat for fourteen hours, and allowed to 

 cool slowly. On opening the tube a great volume of gas was 

 given off, and only a little liquid remained. In the end of the 

 tube which had been the upper end in the furnace, the tube lying 

 obliquely, there was a hard smooth mass adhering to the sides of 

 the tube, and entirely covering the bottom. As I had never ob- 

 tained all the solids in one piece before, I wished to examine it, 

 and so had the other end of the tube cut off, exposing the hard 

 mass. It was quite black, and was removed i\ith a chisel, and 

 as u appeared to be composed principally of iron and lithium, it 



was laid aside for analysis. I was pulverising it in a mortar 

 when I felt that some parts of the material were extremely hard 

 — not resisting a blow, but hard otherwise. On looking closer I 

 saw that these were mostly transparent pieces imbedded in the 

 hard matrix, and on triturating them I obtained some free from 

 the black matter. They turned out to be crystalline carbon, 

 exactly like diamond. I shaU describe further on the analyses, 

 &.C., but mil here go on vith the account of my further experi- 

 ments. Two tubes were filled in the same manner as the last, 

 but one burst on heating, and the other had leaked so that there 

 was no reaction. Two more tubes were prepared, but were 

 spoiled on welding, and on cutting off the carbonised portion the 

 remainder was too short to work. After much , trouble three. 

 tubes were obtained, well closed, in which the three alkali 

 metals were inclosed with liquid containing 20 per cent, bone oil 

 and So per cent, paraffin. All three stood, and, on opening, 

 only the potassium one had leaked to any extent. The results 

 were not good, however, the sodium tube containing only soft 

 scaly carbon, and the other two very little better. The reaction 

 did not seem to have proceeded in the same manner in the 

 lithium tube as before, as the mass was soft and friable. Still, 

 lithium seemed to yield the best results, so it was adhered to in 

 the further experiments. A list of disasters now awaited me. 

 Eight tubes failed through bursting and leaking, and one of the 

 explosions, when two were being heated together, ^destroyed a 

 part of the furnace and injured one of my workmen. Besides 

 this, two tubes were spoiled in welding. However, I had four 

 experiments after this, all withstanding the pressure, and in one 

 of these, with 10 per cent, bone oil and 90 per cent, paraffin 

 spirit, a small quantity of diamond was found. The contents of 

 this tube were different from the other successful one, being 

 much looser and not in the same hard mass as the first. In 

 another series of six experiments two were at 'first thought to 

 have been successful, but I afterwards found that one of them 

 was not so, the transparent matter being siliceous, but insoluble 

 in cold hydrofluoric acid, although it dissolved on boiling. The 

 uncertainty and great expense involved in using these forged coils 

 of iron with tubes bored out of the [solid induced me to again 

 try steel, and Messrs. Cammell and Co., having prepared some 

 tubes for me, I tried them, but with the 'same results — they 

 exploded into fragments at a red heat. And herein they are 

 much more dangerous than coiled tubes, because the latter 

 seldom fly into fragments, but just tear open a little. A further 

 unforeseen danger in using steel tubes was discovered. One 

 which had stood the heating very well was being bored, and 

 when the inner skin was cut so that the gas rushed out, the 

 whole exploded, endangering the life of the workman who was 

 boring, but as he was standing at the end of the tube and the 

 pieces flew laterally, he was not hurt. I have performed over 

 eighty experiments, and have only obtained three results of a 

 successful [nature. The identification of the crystalline pieces 

 as carbon was easy enough, but I have been anxious to find 

 whether they are pure carbon or a compound with some other 

 element, and to that end the following -experiments were 

 conducted. 



A portion of the substance from the first successful experiment 

 was weighed out after it had been freed from all foreign matter 

 adhering to it, and placed in a very small platinum boat made 

 of a strip of thin foil, the ends of which were wrapped round 

 two stout platinum wires which were sealed into a wide glass 

 tube. The carbon particles were transferred to this boat after 

 being weighed, and the tube connected by India- mbber stoppers 

 with an oxygen gasometer on the one side and a series of potash 

 bulbs on the other. The oxygen was dried over solid caustic 

 potash before entering the tube, and again after leaving the 

 potash bulbs. The carbon (14 mgrms.) having been weighed 

 out, the potash bulbs were weighed, and a current of oxygen 

 passed through the apparatus, and the platinum wires connected 

 with a battery strong enough to heat the foil to a bright red-heat. 

 After a few minutes the oxygen was stopped and the bulbs 

 weighed, when it was found that they had gained i mgrm. On 

 repeating this operation no gain was found, the moistm-e having 

 been entirely driven off by the first treatment. The carbon was 

 now placed in the boat, and a slow current of oxygen started, 

 then the bulbs connected and the current made to pass through ' 

 the platinum until all the diamond had been burnt, when the 

 current was stopped and the oxygen allowed to pass for fifteen 

 minutes more, when the bulbs were detached and weighed. 

 They were then reconnected and the gas passed for other ten 

 minutes to find whether all the carbonic acid had been expelled, 



