398 Scientific Intelligence — Miscellaneous. 



standing a few hours in a room at 70° Fahr., to answer very well, 

 when the surface to be plated did not exceed 1^ square inches. The 

 silver solution is made by dissolving cyanide of potassium in water, 

 and adding thereto the oxide of silver. The ratio of the ingredients 

 I am unable to state, as I have not hitherto directed my attention 

 to this point, but have prepared the solution by trial until I obtained 

 the desired result. 



By the process above described, we can at pleasure transfer the 

 tints of the pearl to those pure metals, which will best preserve their 

 brilliancy ; and while the knowledge of this fact is interesting as a 

 matter of science, it may perhaps be well for the artist to consider 

 if it cannot be applied to some ornamental purpose, and the beauty 

 of the precious metals enhanced, by teaching them to glow with the 

 richest hues of light. — {American Journal of Science and Arts, 

 Vol. i., 2d Series, No. 1, p. 112.) 



MISCELLANEOUS. 



43. Progress of the Serial Works of Professor Agassiz. — The 

 various works by this indefatigable naturalist at present appearing 

 in Numbers, have advanced considerably, and the completion of 

 those which Professor Agassiz has not been able to bring to a ter- 

 mination before his departure, will not be retarded by his voyage 

 to America. The third and last part of his Monographic des Pois- 

 sons fossiles du vieux gres rouge, has been published ; and likewise 

 Part 3d of his Histoire Naturelle des Poissons d'eau douce de 

 V Europe Centrale ; fasiculi 7 and 8 of his Nomenclator Zoologicus, 

 continens nomina systematica generum animalium tam vivcntiiim 

 quamfossilium; and, lastly, Part 4th (terminating the Monograph 

 on the Myas) of his Etudes Critiques sur les Mollusques fossiles. 



44. Proposed introduction of the Aracacha into Europe. — On 

 the 3d November 1845, M. Boussingault presented to the Academy 

 of Sciences of Paris, on the part of M. Goudot, a memoir on the 

 cultivation of the Aracacha in New Grenada, and on the possibility 

 of introducing that plant into Europe. The aracacha, which be- 

 longs to the Umbelliferse, yields a very nourishing root. In the 

 Cordilleras of the Andes it is cultivated in localities where the mean 

 temperature varies from 57° to 75° Fahr. (14^ to 24° cent.) The 

 produce of the roots, according to M. Goudot, generally amounts to 

 45,000 kilogrammes per hectare;* and we know that the potato 

 yields about 25,000 to 30,000 kilogrammes of tubers. Owing to the 

 disease which has affected the potato in the present year, M. Goudot 

 has been induced to suggest that new trials should be made to cul- 

 tivate the aracacha in Europe, and in his memoir he suggests the 

 means which are most likely to succeed in reaUzing this introduc- 

 tion. 



* 1 kilogramme = 2-2 lbs. avoird.; 1 hectare =2-47 English acres. 



