Polytechnic Association Proceedings. 591 



are without proof to show that inorganic matter cannot assume 

 guch baneful form, by the process of diffusion through common air, 

 as to carry into the hmgs a poison which may soon disintegrate 

 the blood and pai*alyze the nervous system. It hasj fortunately, 

 been clearly demonstrated that the progress of this unknown enemy 

 through its favorite haunts — the cities — can be prevented by clean- 

 liness, the use of disinfectants, and strict observance of sanitary- 

 regulations. 



SUGAR FROM THE JERUSALEM ARTICHOKE. 



M. Dubrunfant has sent a paper to the French Academy of 

 Sciences on the presence and formation of sugar in the Jerusalem 

 artichoke {Jidianthvs tuberosas). When gathered in September, 

 this tubercle yields a juice which, in the saccharo meter, produces a 

 left-hand rotation of the polarized ray; in contact with yeast, it 

 undergoes a regular alcoholic fermentation, and then deposits a 

 precipitate which is inuliu, and the mother ley which remains is 

 optically neutral. If the tubercle be gathered in March or April, 

 its juice produces a right-hand rotation of the polarized ray; it 

 does not precipitate inulin, and, on being concentrated and treated 

 with alcohol, yields a solution and a gummy precipitate soluble in 

 water and neutral in the saccharometer. The alcoholic solution, 

 on the contrar}^ still gives right-hand rotation of the polarized ray, 

 and, if reduced to a syrup and treated with baryta, precipitates 

 an insoluble sucrate, which, when treated with carbonic anhydride, 

 will dissolve and deposit crystals of pure cane sugar. 



RELATIVE VALUE OF MANURES. 



M. A. Cavalier, of Somme, France, has made experiments with 

 several artificial fertilizers. On ground exhausted by four suc- 

 cessive crops, he obtained, without manure, nineteen hectolitres of 

 wheat per hectare, instead of twenty-eight, the average yield. He 

 proposed to raise on this land beet roots on six plots of ground 

 containing one are each, and separated from each other by a deep 

 furrow. The fertilizer applied to the first plot consisted of five 

 kilogrammes of sulphate of ammonia, two of phosphate of lime, 

 two of common potash and two of lime; to the second plot were 

 added all the ingredients used on the first, except the lime; to the 

 third, five kilogrammes of sulphate of ammonia, two of phosphate 

 of lime, two of lime, but no potash; to the fourth, two kilo- 

 grammes of lime, two of potash, but no nitrogen, to the fifth, five 



