Ramsay and Soddy, and later confirmed by Indrikson, by Débierne, by Curie and Dewar, by Giesel and by Himstedt and Meyer. Helium, a conventional element which is devoid of any evidence of chemical affinity, is produced by or from radium, a conventional element, but the most active substance known. This occurs when the emanation is dry, and we have reason for assuming that the emanation may in reality be an active allotropic form of helium, as ozone is of oxygen.
Recently we have been thoroughly aroused again by Ramsay, who in collaboration with Cameron has not only verified the above statement, but proved that when the emanation is allowed to traverse its downward career in the presence of water, neon and not helium is the gas produced. If the degradation of the emanation be in the presence of a solution of a pure copper salt, sulphate or nitrate, argon and no helium is produced. The emanation becomes one conventional element or another, dependent upon its environment. Helium, neon and argon, with the respective weights, 4, 20 and 40, are produced from the supposititious allotrope of the one with the lowest atomic weight.
We know of no case in which any one of these three obtained from other sources has been converted into the other; nor have we been informed as to whether or not the neon and argon thus produced from the emanation subsequently change into helium.
In this connection it may be stated that Meigen, calling attention to the amount of energy set free in the formation of helium—about 109 great calories for a gram-atom of helium—states that any attempts at reversing this process are rendered hopeless. Nothing is hopeless in science. In fact, many of Ramsay's most fruitful researches have been in the investigation of the unlikely. Can it be, on the other hand, however, that the emanation is in reality a compound of these gases which are characterized by their inertness? Those who have worked with compounds of the rarer elements well know that their scission follows one direction or another, dependent upon ever so slight variations in procedure. If the emanation be, in fact, a compound, which is not likely, it is an endothermic compound involving energy with an order of magnitude far beyond anything with which we are familiar in ordinary chemical reactions. The total heat given off by one cubic centimeter of emanation is equal to about ten million gram calories, or nearly four million times as much heat as produced by the explosion of 1 c.c. of hydrogen and ½ c.c. oxygen.
Ramsay determined the presence of these gases by their spectral conduct. There can be no question of Ramsay's facts, for it is to be assumed that he took the precaution of having the minute quantities of the gases obtained and those in the comparison tubes under similar
- Journal Chemical Society (London), 91, 1605 (1907).
- Nature, 73, 389 (1906).