JiXE 28, 1895.] 



SCIENCE. 



711 



the very best intentions in the matter. The 

 facts were too much for us ; anil all we can 

 do now is to apologise for ourselves and for 

 the gas. 



Several questions maj- be ivsked, upon 

 which I should like to say a word or two, 

 if you will allow me to detain you a little 

 longer. The first question (I do not know 

 whether I need ask it) is, have we got hold 

 of a new gas at all? I had thought that 

 that might be passed over, but only this 

 morning I read in a technical journal the 

 suggestion that argon was our old friend 

 nitrous oxide. Nitrous oxide has roughly 

 the density of argon ; but that, as far as I 

 can see, is the only point of resemblance be- 

 tween them. 



Well, supposing that there is a new gas, 

 which I will not stop to discuss, because I 

 think the spectrum alone would be enough to 

 prove it, the next question that may be asked 

 is, is it in the atmosphere? This matter 

 naturally engaged our earnest attention at 

 an early stage of the enquiry. I will onlj- 

 indicate in a few words the arguments 

 which seem to us to show that the answer 

 must be in the affirmative. 



In the first place, if argon be not in the 

 atmosphei'C, the original discrepanc}' of 

 densities which formed the starting point 

 of the investigation remains unexplained, 

 and the discovery of the new gas has been 

 made upon a false clue. Passing over that, 

 we have the evidence irom the blank exper- 

 iments, in which nitrogen originally derived 

 from chemical sources is treated either with 

 oxygen or with magnesium, exactly as at- 

 mospheric, nitrogen is treated. If we use 

 atmospheric nitrogen we get a certain pro- 

 portion of argon, about 1 per cent. If we 

 treat chemical nitrogen in the same way 

 we get, I will not say absolutely nothing, 

 but a mere fraction of what we should get 

 had atmospheric nitrogen been the subject. 

 You may ask, why do we get any fraction 

 at all from chemical nitrogen? It is not 



difficult to explain the small residue, be- 

 cause in the manipulation of the ga.ses 

 large quantities of water are used: and, as 

 I have already explained, water dissolves 

 argon somewhat freelj-. In the processes 

 of manipulation some of the argon will 

 come out of solution, and it remains after 

 all the nitrogen has been consumed. 



Another wholly distinct argument is 

 founded upon the method of diflusion in- 

 troduced by Graham. Graham showed 

 that if you pass gas along porous tubes you 

 alter the composition, if the gas is a mix- 

 ture. The lighter constituents go more 

 readily through the pores than do the 

 heavier ones. The experiment takes this 

 form. A number of tobacco pipes — eight 

 in the actual arrangement — are joined to- 

 gether in series with india rubber junctions, 

 and thej- are put in a space in which a 

 vacuum can be made, so that the space out- 

 side the porous pipes is vacuous or approxi- 

 mately so. Through the pipes ordinary 

 air is led. One end may be regarded as 

 open to the atmosphere. The other end is 

 connected with an aspirator so arranged 

 that the gas collected is only some 2 per 

 cent, of that which leaks through the poros- 

 ities. The case is like that of an Australian 

 river drying up almost to nothing in the 

 course of its How. Well, if we treat air in 

 that way, collecting only the small residue 

 which is less willing than the remainder to 

 penetrate the porous walls, and then prepare. 

 ' nitrogen ' from it by removal of oxygen 

 and moisture, we obtain a gas heavier than 

 atmospheric nitrogen, a result which proves 

 that the ordinary nitrogen of the atmosphere 

 is not a simple body, but is capable of being 

 divided into parts by so simple an agent as 

 the tobacco pipe. 



If it be admitted that the gas is in the 

 atmosphere, the further question arises as 

 to its nature. 



At this point I would wish to say a word 

 of explanation. Neither in our original 



