xxx GENERAL SUMMARY OF SCIENTIFIC AND 



fare. The needle-gun of Germany was found very much in- 

 ferior to the Chasscpot of France, and both are likely to be 

 superseded by the breech-loaders of American construction. 

 The drift of opinion among experts as to the comparative 

 merits of breech and muzzle loading cannon seems rather to 

 have been settled in favor of the latter, such improvements 

 in the construction of gun-carriages as that of Captain Mon- 

 crieff and others doing away to a considerable extent with 

 the supposed superiority of the former. 



It would require a volume to mention all the discoveries 

 and valuable applications in the department of Technology. 

 For this we must refer to such contemporaries as the Scien- 

 tific American, to the Journal of the Franklin Institute, and 

 other standard chronicles in this branch of science. Among 

 a few, however, that occur to us, we may especially name 

 the method of engraving on stone, glass, and even wood, by 

 means of the continued action of an air-blast of sand, the re- 

 sults as to effect, and the economy of time and expense, being 

 quite marvelous. 



The applications of sundry new dyes to practical purposes 

 have been very numerous, and greatly to the advantage of 

 the dyer's art. Among these may be included artificial ali- 

 zarine, which is now believed to be really superior to the na- 

 tive madder. The methods of extracting aniline dyes from 

 all kinds of fabrics, as announced by Mr. Keimann, promise to 

 be of great practical moment. 



Photographic processes have been improved, especially in 

 connection with the methods of reproducing photographic 

 pictures by such processes as those of Messrs. Albert, Ed- 

 wards, Woodbury, and others. Establishments have been 

 opened in the United States for working under their patents, 

 and bid fair to meet with a measure of success. 



An announcement of much practical value is made in re- 

 gard to the manufacture of glue, namely, that, for the purpose 

 of drying it, the surplus moisture can be best removed by 

 means of contact with salts instead of depending upon evap- 

 oration. The result is a diminution of the time of the opera- 

 tion by many days, which, in the warm weather of summer, 

 may involve the saving of the entire product from injury by 

 decomposition. 



Improved methods for coating metals witli nickel, cobalt, 



