Intelligence and Miscellaneous Articles, 299 



the liquid, its degree of concentration, and the nature of the zinc, ap- 

 peared to me to be the three most important circumstances ; and after 

 having studied them minu-tdy, I arrived at the following results : 

 1st, That the proportion of water and sulphuric acid, which occasions 

 the production of the greatest quantity of hydrogen gas by acting upon 

 zinc, is that in which acid of sp. gr. 1 848 constitutes from 30 to 50 

 per cent, by weight of the solution. 2ndly, That this same propor- 

 tion is that which, put into the voltaic circuit by means of a double gal- 

 vanometer, is the best conductor of electricity. 3rdly, That the dif- 

 ference observed to exist between distilled zinc and that of commerce, 

 appears to be owing to the foreign substances which are mixed with 

 the latter, and particularly iron, which occurs in greater or smaller 

 quantity. 4thly, That the influence of these heterogenous substances 

 appears to have an electrical effect, resulting from their mixture with 

 the more oxidable particles of the zinc." 



" I have made many experiments with different mixtures of dis- 

 tilled zinc, and filings of iron, lead and other metals, and I have al- 

 ways found that the distilled zinc, into which I had thrown one or two 

 per cent, of iron filings while it was melted, was of all, that which gave 

 the strongest evolution of hydrogen with diluted acid ; the zinc of 

 commerce alone produced as much under the same circumstances, the 

 chemical analysis of which showed that it contained a quantity of 

 iron perfectly similar to that of the artificial mixture. That the influ- 

 ence of this iron was electrical, appears to be proved by many circum- 

 stances ; such as the relation which exists between the electrical con- 

 ductibility of the diluted acid and its action upon the zinc, the nature 

 of the action which the diluted acid exerts upon every mixture of zinc 

 and other metals ; and lastly, even the manner in which the effect of 

 these molecular currents may be excited, by inserting in the surface 

 of the distilled zinc a great number of small platina points, instead of 

 mixing it with other filings. 1 ' 



" It appears to me, therefore, that there occur on the surface of the 

 zinc acted upon, a great number of molecular currents, which going 

 from each particle of zinc to each heterogeneous particle occurring in 

 the metal, traverse the acidulated water, and decompose it with the 

 greater facility as its conducting power is good, and produce that in- 

 crease of temperature which always results from the passage of elec- 

 tric currents through aliquid. The order of the electromotive powers 

 of the different mixtures of zinc and heterogeneous metals, and the 

 intensity of the currents to which they give rise, form a series of facts, 

 serving to confirm the preceding explanation.'' 



As to the causes which produce electricity, M. Delarive observes : " I 

 have ascertained that contact alone, unconnected with any efficient 

 cause, cannot by itself occasion electricity, either in the form of cur- 

 rents or in that of tension. Independently of the processes which I have 

 already described, I have employed others, such as using condensers 

 of different kinds, and condensers placed in different media; and if 

 by this last process I have arrived at results which differ frum those of 

 M. Pfaff, it is, as I have ascertained, because the smallest quantity of 

 moisture remaining in the air or in a gas, occasions a chemical action 



2 Q 2 upon 



