414 



The Hon. J. W. Strutt on the Rejjroduction of [June 20, 



experiments recorded in No. 89 of the ' Proceedings of the Royal Society ' 

 (vol. xv. p. 339). 



The effect on the free acidity of the urine was inconsiderable. The 

 free-acidity may have been a little increased in the brandy period, but the 

 change was slight. 



The effect on the chlorine was not certain, as its ingress was not suffi- 

 ciently constant, but it seems to be lessened in the exercise period. 



As the action of alcohol in dietetic doses on the elimination of nitrogen 

 and on the bodily temperature is so entirely negative, it seems reasonable 

 to doubt if alcohol can have the depressing effect on the excretion of pul- 

 monary carbon which is commonly attributed to it. It can hardly depress, 

 one would think, the metamorphosis of tissues, or substances furnishing 

 carbon, without affecting either the changes of the nitrogenous structures 

 or bodily heat. It seems most important that fresh experiments should 

 be made with respect to its effect on carbon elimination, as without a per- 

 fect knowledge on that point the use of alcohol as an article of diet in 

 health cannot be fairly discussed. 



IV. cc Report on Scientific Researches carried on during the Months 

 of August, September, and October, 1871, in H.M. Surveying- 

 Ship c Shearwater/" By William Carpenter, LL.D., M.D., 

 E.R.S. Received June 13, 1872. 



[This paper will appear in full in a future Number of the ' Proceedings.'] 



June 20, 1872. 



Sir JAMES PAGET, Bart., D.C.L., Vice-President, in the Chair. 



Prof. William Grylls Adams, Dr. Andrew Leith Adams, Dr. John Cle- 

 land, Dr. Michael Foster, Prof. William Stanley Jevons, and Dr. William 

 James Russell were admitted into the Society. 



The following communications were read : — 



I. " Preliminary Note on the Reproduction of Diffraction-gratings by 

 means of Photography." By the Hon. J. W. Strutt, M.A. 

 Communicated by Prof. G. G. Stokes, Sec. R. S. Received May 

 23, 1872. 



During the last autumn and winter I was much engaged with experi- 

 ments on the reproduction of gratings by means of photography, and met 

 with a considerable degree of success. A severe illness has prevented my 

 pursuing the subject, for some months, and my results are in consequence 

 still far from complete ; but as I may not be able immediately to resume 

 my experiments, I think it desirable to lay this preliminary note before the 



