130 Chemico- Galvanic Observations. 



opposite direction : but the result of some experiments I 

 have made is not favourable to this hypothesis, and I am 

 rather inclined to believe that the roots disperse themselves 

 in every direction, and only become most numerous where 

 they find most employment, and a soil best adapted to the 

 species of plant. My experiments have not, however, been 

 sufficiently varied, or numerous, to decide this question, 

 which I propose to make the subject of future investigation, 



{ am, &c. 

 Elton, T. A. Knight, 



Nov. 22, 1805. 



XXII. Chemico- Galvanic Observations communicated to the 

 National Institute of Italy. By M. L. Brugnatelli. 



[Concluded from p. 66.] 



§ VII, 



Various Coatings, Incrustations, and other particular Com-? 

 positions, are produced by galvanizing Metals in pure 

 Water. 



W ires of very pure gold, plunged in distilled water and 

 submitted to the Galvanism of the positive pole, in a sepa- 

 rate tube, are covered in a few hours with a subtle coating 

 and crust of a saffron yellow colour. This is not observed 

 upon gold wires alloyed with copper, nor upon those of pure 

 gold when negatively galvanized. But the same yellow coat- 

 ing is observed upon platina wires, whether the piles be of 

 middling or more energetic force. 



The nature of these incrustations has not been exactly 

 ascertained. It seems that they ought to be attributed to a 

 commencement of the solution of the metal by means of the 

 oxymuriatic acid which is produced in the experiment. 



The other metals present singular combinations. Some 

 of them are oxidated ; some combine, with hydrogen ; others 

 unite with pure water by the Galvanic influence. The fol- 

 lowing are the details : 



(a) Hydro* 



