380 



The Burgund}^ and Claret have less alcohol than was found by 

 Mr. Brande forty years ago in the wines he examined. The Sherry 

 is now stronger, the Port is not so strong, the Marsala is weaker, 

 the Rhine wine is the same strength, the Brandy is as strong 

 as formerly ; the Rum is nearly half as strong again ; the Porter is 

 stronger, and the Stout rather stronger than formerly. 



Lastly, the specific gravity of each liquid was taken. As this 

 however chiefly depends on the amount of alcohol and sugar present, 

 and as these were directly determined, the specific gravity may be 

 taken as a distant control on the amount of sugar present. 



Thus, in those wines in which the amount of alcohol was the 

 same, the specific gravity was found to vary with the amount of 

 sugar found by the saccharometer. 



The results of the analysis of each sample of wine, kc. is given 

 in a series of tables, which do not admit of any abstract. 



December 22, 1853. 

 THOMAS GRAHAM, Esq., V.P., in the Chair. 

 The following papers were read : — 



1 . " An Inquiry into some of the circumstances and principles 

 which regulate the production of Pictures on the Retina of the Hu- 

 man Eye, with their measure of endurance, their Colours and 

 Changes." By the Rev. W. Scoresby, F.R.S., Corresponding Mem- 

 ber of the Institute of France, &c. Received Nov. 19, 1853. 



The investigations of the author embrace three distinct cases, — 

 the case of achromatic pictures ; that of coloured pictures of un- 

 coloured objects, derived simply or mainly from the influence of light 

 on the eye ; and that of the spectra of coloured objects, together 

 with certain applications of the results obtained to other optical 

 characteristics, determinations or phenomena. 



The general mode of experiment employed in these researches is 

 described as " the viewing of illuminated objects with a steady fixed 

 gaze at a special point, and then determining the impression on the 

 retina by examining the images developed ivith closed eyes." The 

 time of viewing the objects varied from a momentary glance up to 

 half a minute, more rarel)^ to a minute ; and the mode of eliciting 

 the impression was, primarily, by closing the eyelids into gentlest 

 contact, whilst the head was kept unmoved, and the eyelids steady 

 in their original direction. Thus performed, the experiment becomes 

 very simple and manageable, and the results, various as they are in 

 colour or depth of tint, are almost unfailingly elicited and often 

 curious or beautiful. 



Whilst the general result of viewing an illuminated object is the 

 production of a clearly- defined picture on the retina, appearing in 

 certain cases instantly, or more commonly, from 3 to 5 seconds after 

 the eyes are closed, — the nature or quality of the picture, with its 



