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VII. Outlines of Experiments and Inquiries respecting Sound and 

 Light. By Thomas Young, M. D. F. R. S. In a Letter to 

 Edward Whitaker Gray, M. D. Sec. R. S. 



Read January 16, 1B00, 



DEAR SIR, 



It has long been my intention to lay before the Royal Society 

 a few observations on the subject of sound ; and I have endea- 

 voured to collect as much information, and to make as many 

 experiments, connected with this inquiry, as circumstances 

 enabled me to do ; but, the further I have proceeded, the more 

 widely the prospect of what lay before me has been extended ; 

 and, as I find that the investigation, in all its magnitude, will 

 occupy the leisure hours of some years, or perhaps of a life, I 

 am determined, in the mean time, lest any unforeseen circum- 

 stances should prevent my continuing the pursuit, to submit to 

 the Society some conclusions which I have already formed from 

 the results of various experiments. Their subjects are, I. The 

 measurement of the quantity of air discharged through an aper- 

 ture. II. The determination of the direction and velocity of a 

 stream of air proceeding from an orifice. III. Ocular evidence 

 of the nature of sound. IV. The velocity of sound. V. Sonorous 

 cavities. VI. The degree of divergence of sound. VII. The 

 decay of sound. VIII. The harmonic sounds of pipes. IX. The 

 vibrations of different elastic fluids. X. The analogy between 

 light and sound. XI. The coalescence of musical sounds. XII. 



