CHEMISTRY. 



123 



showed that they were both very rich in calcium 

 carbonate. The organisms coining from various 

 parts of the country seemeil l<> br \ cry uniform in 

 regard to their ability to endure acidity. " If these 

 results are again obtained when the tests are re- 

 JM ated with the pure organisms isolated from the 

 different soils, the interpretation to be given them 

 is a very important one; these results are to be 

 looked upon as evidence that we are to seek prac- 

 tical results in the study of the nitrifying organ- 

 isms, not from a search for a peculiarly active spe- 

 cies, but from a search for those conditions that are 

 most favorable to the activity of these organisms in 

 any given set of soil and climatic conditions. 



E. H. Farrington has noticed in the course of his 

 experiments with milk preservatives that the acid- 

 ity of milk is increased by boracic acid (or preserva- 

 line). Milk treated with'it required an abnormally 

 large quantity of one tenth normal alkali to neu- 

 tralize it, and much more .than water in which the 

 same amount of " preservaline " was dissolved. 



Miscellaneous. Although, say A. A. Bennett 

 and E. E. Pammel, the study of the products of 

 chemical decomposition forme'd by micro-organisms 

 has not been very extensive or very thorough, yet 

 much has been learned in a qualitative way. The 

 substances produced by bacteria are fairly numer- 

 ous, and include solid's, liquids, and gases. The 

 same substances are often produced by micro- 

 organisms in varying proportions. Among the 

 solids produced are the ptomaines, indol, skatol, 

 leucine, tryosine. suceinic and malic acids, etc. 

 The liquids include alcohol and acetic and lactic 

 acids. Numerous gases are formed, among which 

 are hydrogen sulphide, ammonia, carbon dioxide, 

 hydrogen, and methane. When in some cases am- 

 monia and hydrogen sulphide are produced simul- 

 taneously, they unite and form ammonium sulphide. 

 The importance of the study of these products is 

 evident when the character of the ptomaines and 

 leucomaines, tuberculin, antitoxine. etc., is con- 

 sidered. A knowledge of the gaseous products and 

 the conditions under which they are formed is often 

 of great value to the biologist in identifying differ- 

 ent species. In a study of them by the authors an 

 attempt was made to estimate accurately the con- 

 stituents of the mixed gaseous products by a variety 

 of bacteria. The results of their investigations are 

 given with considerable minuteness of detail, but no 

 general conclusions are stated. The results of sim- 

 ilar studies by Dr. Theobald Smith are, however, 

 cited, as showing that the media conditions under 

 which development took place modified the propor- 

 tion of the gaseous products and the rapidity of their 

 formation. They also show that these facts may be 

 used to a marked extent to determine species. 



A new apparatus for the liquefaction of air and 

 other gases, patented by Dr. William Hampon, con- 

 sists of three coils of narrow copper tubing, ar- 

 ranged concentrically in a metal case, and con- 

 nected successively. The gas say oxygen enters 

 the outer coil under a pressure of 120 atmospheres. 

 passes from this into the second, and from this 

 into the central coil, which is surrounded by a 

 cylindrical glass vacuum-jacketed vessel. The 

 two outer coils are separated from each other 

 by vertical divisions of the case, and the spiral 

 of the central coil is followed by a flat spiral 

 of sheet copper. When the gas reaches the end of 

 the central coil, it escapes through a fine orifice of 

 peculiar construction, the size of which can be 

 regulated by means of an ebonite rod adjusted for 

 the purpose. After its escape the whole of the gas 

 cooled by expansion passes through the space sur- 

 rounding the pipe through which the compressed 

 gas is pressing to the point of expansion, and so 

 makes this gas, still under pressure, cooler than it 



was itself while under compression. The com- 

 pressed gas consequently becomes at the point of 

 expansion cooler than that which preceded it, and 

 in its turn follows backward the course of the still 

 compressed gas, and so makes the latter cooler than 

 before expansion, and therefore also cooler than 

 even after expansion. This intensification of cool- 

 ing (always assuming sufficient protection against 

 access of heat from the outside) is limited only by 

 the liquefaction of the gas. which, in the case of 

 oxygen, takes place at 180 C. 



In his presidential address before the chemical 

 section of the British Association, Dr. Ludwig 

 Mond presented the history of the manufacture of 

 chlorine as a process which has been influenced and 

 perfected in an extraordinary degree by the rapid 

 assimilation and application of the results of purely 

 scientific investigations and scientific theories, and 

 as offering a very remarkable example of the incal- 

 culable value to commercial interests of the prog- 

 ress of true science. 



A comparison, made in Wollny's " Forschungen," 

 of the proportions of carbonic-acid gas in samples of 

 air obtained near the earth's surface with that of sam- 

 ples collected by S. A. Andree at various altitudes, 

 failed to prove any diminution of carbonic dioxide 

 with altitude up to the highest point, 4,300 metres, 

 reached in the balloon ascensions. On the other hand, 

 the percentages of the gas by volume throughout the 

 different strata of air are very much the same as those 

 observed at the surface of the earth. An apparent 

 dependence on the wind was, however, suggested by 

 the results, and when the percentages were dis- 

 cussed from that point of view, the general conclu- 

 sion arrived at was that a descending mass of air 

 brings with it a higher percentage of carbonic-acid 

 gas, which is subsequently diminished by absorption 

 near the earth's surface, so that the descending cur- 

 rent has a smaller percentage. A very important 

 question is raised here in the theory of the interac- 

 tion of the atmosphere and the earth. 



Zinc has been observed by K. Colson to exert an 

 energetic action upon platino-bromide. If we clean 

 with sandpaper a portion of leaf zinc which has 

 been left to itself for some time, and bring it into 

 contact with a gelatino-bromide plate for about 

 twenty-four hours, development causes a gray tint 

 to appear opposite the cleaned part, and a lighter 

 gray opposite the parts still bright, though not re- 

 cently cleaned, while hardly anything appears oppo- 

 site the oxidized parts. This action appears also at 

 a distance and through certain bodies. The cause 

 seems to be vapor of zinc. Magnesium and calcium 

 give the same effect, but nothing is obtained with 

 lead, tin, copper, iron, and aluminium. M. H. Pillat 

 mentions that he has obtained similar results with 

 steel. He ascribes them to the influence of a metal 

 upon the nature of the surface of another metal 

 placed at a little distance. 



Since its introduction into surgery by Sir Benja- 

 min Richardson peroxide of hydrogen, says Mr. C. 

 A. Fawcett. has not become so popular as was an- 

 ticipated. It possesses undeniable advantages, as, 

 for example, when its oxygen is given off only 

 water remains. On the other hand, it lias the dis- 

 advantages of irritability and instability. The for- 

 mer is due to the presence of acids, usually hydro- 

 chloric acid, and solid matter. This may be avoided 

 by exercising great care in the preparation. The 

 instability of the peroxide of hydrogen varies with 

 the method of preparation adopted : whenever it is 

 practicable the substance should be diluted to the 

 strength required in practice and kept in a dark 

 place. 



Herr Ed. Spaeth sums up the results of his experi- 

 ments on the rancidification of fats as follow: 1. In 

 the rancidification of fats (hog's lard), which must 



