3 74 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



USE OF SEWER- WATER AS A MANURE. 



According to the Revue Horticole, experiments with the 

 sewer-water of Paris, in the cultivation of certain lands be- 

 low the level of the city, commenced three years ago, have 

 been of the most satisfactory character, and the eagerness 

 that the farmers now exhibit to obtain permission to use 

 these waters on their lands, wherever it is practicable, is jus- 

 tified by the great increase in their value, many of them hav- 

 ing previously been of little worth. Thus certain lands now 

 rent for six and seven times as much per annum as formerly. 

 Revue Horticole, January 15, 1872, 22. 



KEEPING GRAIN IN VACUO. 



Some time ago Dr. Louvel suggested the idea of keeping 

 grain in a partial vacuum, by introducing it into air-tight 

 vessels and exhausting the air, this being intended to prevent 

 injury from dampness, and to secure it from the attacks of 

 insects as well as vermin. We now learn that this idea has 

 been brought to a practical test, and that it bids fair to en- 

 ter largely into the operations of grain-dealers. For the 

 purpose in question, vessels are made of boiler-iron, to con- 

 tain about twenty-seven bushels ; and after the grain is in- 

 troduced and the cover applied, a vacuum is effected, which, 

 for this purpose, need not involve a reduction of pressure of 

 over one sixth to one seventh of the ordinary atmosphere. 

 Any number of these receptacles can, of course, be made, and 

 can be used over and over again indefinitely. 1 A, March 8, 

 1872,118. 



RATIO OF NITROUS TO NITRIC ACID IN RAIN-WATER. 



As the result both of recent and of earlier observation, it 

 has been found that the ratio of nitrous to nitric acid in rain- 

 water depends upon the degree of heat, moisture, and elec- 

 tricity of the atmosphere. The conditions favorable to the 

 production of nitrous acid are calm and cloudy weather, a 

 mean temperature, and an elevated hygrometric condition ; 

 while, on the other hand, the production of nitric acid is fa- 

 vored by a high temperature, a dry atmosphere, high winds, 

 and thunder-storms. 21 A, April, 1872, 281. 



