264 Notice of a peculiarity in Vision. 



carbonate. Again a stream of carbonic acid passed through 

 a solution of the chloride, effects a decomposition in a few 

 hours, or at least, to so great an extent, that it no longer acts 

 on vegetable colors or putrid substances — and at the same 

 time carbonate of lime is formed. Now the conversion of 

 lime into carbonate, by the contact of carbonic acid is not 

 remarkable, and the evolution of chlorine is not to be re- 

 garded as an evidence of the decomposition of a compound 

 of chlorine and lime or soda. 



For the purpose of settling the latter assertion by experi- 

 ment, I charged some rain water with chlorine until it bleach- 

 ed powerfully. On passing through it a stream of carbonic 

 acid, or simply blowing into it through a glass tube for half 

 an hour, the chlorine was so far discharged as to leave the 

 solution without action upon indigo or turmeric. This re- 

 sult, I ascribe to the mechanical effect which the passage of 

 a gaseous substance has, in bringing successive portions of 

 the solution into contact with the air, and thus facilitating 

 the evolution of chlorine. 



Now when carbonic acid is passed through a solution of 

 the supposed chloride of lime, it combines with the lime and 

 is precipitated in the form of carbonate. There remains 

 then, a simple solution of chlorine in water from which chlo- 

 rine is disengaged by the carbonic acid as before stated. But 

 when this gas is transmitted through a solution of soda, car- 

 bonate of soda is formed which is soluble, and the chlorine is 

 then more difficultly disengaged for the reasons which have 

 been suggested, when noticing the difference in the effect of 

 ebullition upon simple solutions of chlorine in water, and 

 upon various saline solutions charged with chlorine. .In this 

 way we can also account for the inefficiency of carbonic acid 

 in removing the chlorine from Labarraque's liquid, as stated 

 by Mr. Faraday. Further experiments seem still necessary 

 to decide whether the disengagement of chlorine from lime, 

 soda and carbonate of soda in solution, during the process of 

 disinfection, is produced in each, in the same manner. 



Art. V. — Notice of a peculiarity in Vision; by Chauncey 

 E. Goodrich. 



From my early years I have been sensible of a want of 

 precision of eye sight. My eyes too, for the first eighteen 

 years of my life, were occasionally weak and sore ; but ha- 

 bitual study has strengthened them so that now they seldom 



