416 



SCIENCE. 



[N. S. Vol. VIII. No. 196. 



are greatly altered by electrical charges. 

 Oa the other hand, what we know as free 

 potassium is a solid substance whose mole- 

 cules consist of potassium atoms not charged 

 with electricity at all. * * * As soon as the 

 potassium atoms in solution lose their 

 charge, as they do, for example, when led 

 by an electric current to a platinum wire, 

 where they can give up their electricity, 

 potassium with its ordinary properties is at 

 once produced." 



A further consequence of osmosis and 

 that of free ions in solution is Nernst's 

 theory in regard to the electric current in 

 the voltaic cell — the little instrument sent 

 into the world a century ago, from which 

 have come such epoch-making results, so 

 that one cannot help but be profoundly im- 

 pressed with the time-honored words : 

 ' Despise not the day of small things.' 



However, it is not alone in the field of 

 pure chemistry that helpful and interesting 

 consequences of the introduction of the 

 ' subtile agent' are found. The patient, 

 careful analyst, as he struggles to unravel 

 the problems Nature has placed before him, 

 will ever hold sacred the name and memory 

 of our own Dr. Gibbs, who in 1865 first 

 called the attention of the chemical world 

 to that simple yet beautiful and extremely 

 satisfactory determination of copper in the 

 electrolytic way which proved the incentive 

 to further study in this direction, so that at 

 present twenty-one metals lend themselves 

 to electrolytic determination from solutions 

 of the most varied character, and in the 

 same manner at least one hundred and 

 twenty separations have been made, all of 

 which for accuracy, neatness and rapidity 

 leave little to be desired. 



In the commercial manufacture of potas- 

 sium chlorate, potassium persulphate, caus- 

 tic, iodoform, etc., etc., those who seek to 

 apply the principles of chemistry in the es- 

 tablishment of industries of national im- 

 port have found in the current a most fruit- 



ful aid, the full consequences of which are 

 yet untold. 



But it was not to any one of these I es- 

 pecially desired to direct your attention. 

 As indicated by my subject, I had in mind 

 another thought and, craving your further 

 indulgence, I shall at once proceed to a new 

 chapter in this historical resume, of electro- 

 chemistry. 



You are all familiar with the classic ex- 

 periment made fifty years ago (1848) by 

 Kolbe. I refer to the electrolysis of con- 

 centrated solutions of potassium acetate and 

 valerate. You remember that this was the 

 first investigation of its kind in the domain 

 of organic chemistry. The results were 

 most interesting and were thought to have 

 shed a new light upon and given deeper in- 

 sight into the constitution of compounds. 

 In the case of potassium acetate the course 

 of the decomposition was considered as be- 

 ing fully represented by the resulting prod- 

 ucts: 



+ - + - 



CHj. CO, K HOH 



+ 

 CHj. COj K HOH 



CH, COj KOH-fH 



I + + 

 CHa CO,, KOH H 



It was held to be a very simple decomposi- 

 tion. 



Kekule, in 1864, gave to the world facts 

 gathered by him in the electrolysis of di- 

 basic acids, e. g., succinic, fumaric, maleic, 

 and brom-male'ic acids. The first gave hy- 

 drogen and ethylene, together with carbon 

 dioxide ; the two isomeric acids gave acety- 

 lene, while brom-maleic acid was thought 

 to have yielded brom-acetylene. In 1866 

 Brester subjected various aliphatic bodies 

 to electrolysis, but obtained nothing new. 

 Aarland next followed with his study of the 

 three isomerides — citraconic, itaconic and 

 mesaconic acids, or the allylene dicarboxylic 

 acids, as they may also be termed. Aarland 

 expected that when these three bodies were 

 subjected to electrolysis they would yield 

 three isomeric allylenes. He also purposed 



