262 ANNUAL OF SCIENTIFIC DISCOVERY. 



one to three drachms of the flour are to be introduced into this tube, which 

 is next to be nearly filled with chloroform. The tube is now to be corked, 

 well shaken, and left awhile at rest, until the separation has had time to 

 take place. The flour rises to the surface of the chloroform, while the 

 mineral adulteration falls to the bottom, and may be submitted to analysis 

 in order to detect its exact nature. Moniteur des Hop. 



ANALYSIS OF FISH SCALES. 



At a recent meeting of the Boston Society of Natural History, Mr. John 

 Green gave the results of an analysis of the scales of the striped bass (Lab- 

 rax Lineatus), as follows, viz. : 



In scales dried at 212 F., 45'9 per cent, of ash. 100 parts of ash contained 

 of lime, 48 - 36; of magnesia, *99; of phosphoric acid, 50 - 65. This result is 

 identical with the composition of bone ash. The structure of bone is differ- 

 ent in the Ganoid fishes from that of any Cycloid or Ctenoid, and confirms 

 the differences already established from the appearances of the scales. The 

 scales of the Amia, of the western waters, contain bone corpuscles of the 

 same form and appearance as those of Megalops and Lepidosteus, showing 

 a new analogy of Amia with Ganoid fishes. 



ON THE DETECTION OF ORGANIC IMPURITIES IN THE AIR. 



At a recent meeting of the London Chemical Society, Dr. Augustus Smith 

 stated that he had for several years paid particular attention to the con- 

 dition of the air of towns, and had, during that time, frequently endeav- 

 ored to obtain a ready mode of estimating the organic matter present in it. 

 Until recently, however, he had not found any satisfactory method of so 

 doing : but now, by the adoption of a new process, results before requiring 

 days or weeks of experimenting, could be obtained in a half an hour. The 

 method devised consists in finding how much of a solution of permanganate 

 of soda will be decomposed by a given amount of air. The indications given 

 by this are very beautiful, and illustrate those truths which sanitary econo- 

 my has long been teaching, with indifferent success, to the country. I find, 

 says Dr. Smith, as much difference between the back streets of a town and 

 the air of a hilly district, as from 1 to 22. In other words, there was found 

 in the air of a close court 22 times more matter capable of decomposing the 

 solution, than there was found in a free, hilly district. Some of the results 

 obtained, when tabulated, are as follows : 



A definite amount of a standard solution of the salt was decolorized by 22 

 measures of air from the high ground in the neighborhood of Preston, by 9 

 measures of air from an open street in Manchester, by 5% measures of air 

 from between some small houses on the banks of the Medlock river, by 2 

 measures of air from a closed carriage full of passengers, and by 1 measure 

 of air from the back yard of a house in a low and closely -built neighbor- 

 hood. 



Mr. Smith terms the means thus employed the sepometer. Its delicacy is 

 such that it registers many steps lower than the point of which the ordinary 

 smell is . capable of taking cognizance. It clearly and distinctly tells the 

 state of ventilation in a room. 



Mr. Smith has also observed a very noticeable difference when blood was 

 agitated with different varieties of air. Contrary to expectation, the air of 



