284 Experiment to prcferve Potatoes, 



This effeft, as the author conjeftures, arifes from the ni- 

 trous acid which the nitrous air contains. The author com- 

 municated alfo the ib'Iowing obfervation : — Being defirous, 

 as the late Camper was, to difcover I'ome means for prevent- 

 ing potatoes from growing, in order that they might be pre- 

 ferved in a date fit for food throughout the whole vear, he 

 put fixty of them into a glafs bell with fixed air, and clofed 

 the aperture with mercury. The potatoes, indeed, did not 

 germinate, but at the end of fix months thcv were totally 

 fpoiled, emitted a brown corrupted juice^ and Hunk moll 

 intolerably. 



Dr. G. H. Thilow read a paper on the aftion which puri- 

 fied nitre and common fait have on the animal body. From 

 feveral experiments which the author made in the galvanic 

 manner, with many variations, on different animals, he con- 

 cludes, that nitre poiTeffes the property o': lowering the tone 

 of the nervous and mufcular fibres. Thus, for example, the 

 crural nerve of a frog being tlrewed over with nitre, no con- 

 vulfive movements of irap'vtance took place ; but when com- 

 mon fait was applied in the fame manner, exceedingly violent 

 convulfions were produced. The author is therefore of opi- 

 nion, that common fait is to be confidered as one of the 

 flrongefl of fiimulants. 



In the fitting of November 2, J. F, H. Baron von Dalberg 

 prefented a treatife on the origin of harmony, and its pro- 

 greflivc formation. In this clfay the author traces out the 

 progrefs of the mufical gamut of melody and polyphcnia, 

 or finging in parts, in the different periods of the hiftory of 

 mufic from their firft origin to their prefent refined ftate; and 

 {hows, by hiftorical and jifthetic proofs, that all the arts, in 

 regard to their formation, have had the fame progrefs; that 

 is, from fimplicity to complexnefs, from rudcnels to refine- 

 ment, from great to exalted, until the art, by corruption of 

 tade, again finks into trifling minutenefs, and becomes over- 

 loaded and fpoiled. From thefe obfervations the author de- 

 duces this practical refult for muficians, that unity and va- 

 riety determine real beauty; that difcords, chromatic and 

 enharmonic proportions, the alternation of quick and flow 

 time, and a mixture of the exalted and lively ftyle, are ne- 



ccffury 



