1897.] DISCUSSION. 137 



rather a free and unguarded kind of way, having a theory of his own 

 supplementing that of Engler, his theory being that Engler's distil- 

 lates in their original conditions were more like the bituminous shale 

 oils than true petroleum ; and that it needed this after-treatment witli 

 the aluminum chloride to bring them at all in character to corre- 

 spond to petroleum oil. He therefore believed — assuming Engler's 

 theory of the animal origin of oils — that these animal remains had 

 first of all been subjected to a distillation analogous to that with 

 bituminous shales ; and that a supplemental reaction with heat 

 and contact with certain metallic chlorides — like the aluminum 

 chloride, had transferred them into a secondary product, that is, the 

 mixed petroleum or rock oil. The thing looked like a very fine 

 solution of the question, but I have also noticed within the last six 

 weeks two other articles published in the same journal, in which 

 other authorities have claimed that this aluminum chloride re- 

 action is a fallacy : that it does not by any means give a pure 

 mixture of hydrocarbons belonging to the paraffin series and is 

 absolutely worthless as a means of purification. It is stated that it 

 cannot be carried out in the hands of any one except the gentleman 

 who first published it. Prof. Day alludes to the possibility of 

 sodium chloride playing an important part in the matter of produc- 

 ing these hydrocarbons of the Pennsylvania type from sulphur and 

 oils similar to the Ohio type of oil. I doubt very much whether it 

 is worth while to bring that in j because the thing seems to be dis- 

 credited and that part, of course, will have to drop away. 



There is something to be said in favor of the question of filtration 

 that Mr. McGonigle speaks of. As to whether the sulphur could 

 be eliminated by that or any sodium chloride reaction I doubt ex- 

 tremely ; and therefore the theory which is presented by Dr. Day 

 has several quite important breaks in it. 



I need hardly make any comment upon the very interesting 

 papers we have heard, first of Prof. Peckham and afterwards of Prof. 

 Mabery. I have been acquainted for some time with Prof. Peck- 

 ham's views with regard to liquid asphaltum and the way in which 

 the change from petroleum may take place ; and there is an immense 

 field, doubtless, there, to be opened and studied ; and then of course 

 the whole thing is modified and very much complicated by the 

 existence of what he calls hydrates of certain of these organic 

 acids which are present ; and then the presence of these pyridine 

 bases also has some modifying effect. 



