8(3 
THE HON. Sm CHARLES ALGERNON PARSONS: EXPERIMENTS ON 
electrically heated at any pressure up to 4400 atmospheres, and in a few experiments 
up to 6000 atmospheres. 
That at 15,000 atmospheres carbon and graphite electrically heated are either 
directly transformed into soft graphite or are first vaporized and then condensed as 
such. 
While the experiment of rapidly compressing a mixture of acetylene and oxygen 
and the production of temperatures much in excess of that necessary to vaporize 
carbon, accompanied by a momentary pressure of about 15,000 atmospheres, confirms 
the conclusion that the negative results obtained in the attempts to convert graphite 
into diamond by electrical heating are not due to lack of temperature ; on the other 
hand, the presence of minute crystals in the molten layer of the steel of the end of 
the barrel subjected to high gaseous pressures of carbon monoxide, carbon dioxide, 
and hydrogen appears to be connected with the other experiments bearing upon the 
inclusion of gases in metal as a factor in the production of diamond. 
The experiment of firing a high velocity steel bullet with cupped nose through 
vaporizing carbon into a hole in a block of steel has tested the effect of a momentary 
pressure of about 300,000 atmospheres on carbon initially near its melting-point, and 
probably raised by adiabatic compression by another 1000° C. 
The fact that only a very few minute crystals resembling diamond were produced 
(probably from the iron) raises the question as to whether the duration of the 
pressure is sufficient to start a transformation of graphite to diamond which can be 
detected by analysis. We have distinct evidence that, with iron as the matrix, the 
time is sufficient to form very small crystals which can be identified with some 
certainty, so it therefoi’e seems reasonable to conclude that there was no incipient 
transformation in bulk, and that however long the pressure of 300,000 atmospheres 
were applied, it is extremely doubtful if any change would occur. 
The pressure of 300,000 atmospheres is between one quarter to one half that 
obtaining at the centre of the Earth, but vastly greater pressures exist at the centre 
of the larger stars, and are produced by the collision of large bodies in space; these 
pressures are many thousands of times greater, and whether they would effect the 
change it is impossible to predict.. On the other hand, a heating effect on large 
masses of iron might be produced by collisions, and owing to the heat generated by 
adiabatic compression of the central portions, some of the mass would be melted 
and subsequently cooled on release of the pressure, so that if heating and cooling 
under pressure are alone necessary for the production of diamond large stones might 
result. These considerations, though of interest as bearing upon the presence of 
diamonds in meteorites and also indicating a possible origin of natural diamond, are 
of no practical value to us because the pressures required are entirely beyond our 
reach. There are, however, other considerations ari^ng out of the experiments of 
Marsden, Moissan, and Crookes, as well as our own, which seem to give some hope 
of solutions of the problem at issue which lie within the means at our disposal. 
