cclxxxii GENERAL SUMMARY OF SCIENTIFIC AND 



sulphurous acid. (4.) Ramsay's bleaching bath is formed 

 by sprinkling with water equal parts of chloride of lime and 

 sulphate of magnesia, by which process the hypochlorite 

 of magnesia is produced. This last process is highly spoken 

 of. 



Upon the subject of ozone, Dr. Hofmann offers this stimu- 

 lus to investigators in his late "Report on the Development 

 of the Chemical Arts during the last Ten Years:" "How 

 great would be the influence of a cheap source of ozone 

 upon manufactures appears at once from the fact that in 

 the nascent state this body oxidizes nitrogen to nitric acid. 

 The presence of the latter body in thunder-rain has long 

 ago been found to result from this circumstance. The man- 

 ufacture of ozone would therefore involve nothing less than 

 the synthesis of this important mineral acid, obtained hither- 

 to only from nitre. That in grass-bleaching and in disinfec- 

 tion by means of ethereal oils we have from time imme- 

 morial made use of ozone generated in the one case by 

 the growth of grass, and in the other by the hydrocarbons 

 can only serve to intensify our longing for the technical 

 production of ozone." Dr. Hofmann refers also to the met 

 that the first patent for the application of ozone was re- 

 cently granted in England, for the purpose of forming 

 acetic acid from alcohol without fermentation. The inven- 

 tors (Turner and Vanderpool) obtain ozone by blowing air 

 through a flame, and bringing it in contact with a current 

 of alcohol. A very similar process for obtaining ozone was 

 patented in this country, it may be added, by Dr. Loew, but 

 no account of its practical application has thus far trans- 

 pired. 



The Chemical N~ews, in its notes from foreign sources, af- 

 fords the following information concerning Hofmann's proc- 

 ess of utilizing iron pyrites. It is well known that the sul- 

 phur employed in the manufacture of sulphuric acid was 

 formerly obtained from Sicily in its native state. In conse- 

 quence, however, of the considerable increase in the export 

 duties levied thereon during the last twenty years, the at- 

 tempt was successfully made to supersede the sulphur by 

 iron pyrites. The extraction of these pyrites is only found 

 profitable where they occur in large masses. The residues 

 likewise contain such large proportions of iron (about forty 



