CONTENTS. 
I. The Croonian Lecture. In which some of the morbid Actions 
of the straight Muscles and Cornea of the Eye are explained, 
and their Treatment considered. By Everard Home, Esq. 
F. R. S. page 1 
II. Observations on horizontal Refractions which affect the Ap- 
pearance of terrestrial Objects , and the Dip, or Depression of 
the Horizon of the Sea. By Joseph Huddart, Esq. F. R. S. 
P- 29 
III. Recherches_ sur les principaux Problemes de V Astronomie 
Nantique. Par Don Josef de Mendoza y Rios, F. R. S. Com- 
municated by Sir Joseph Banks, Bart. K. B. P. R. S. p. 43 
IY. On the Nature of the Diamond. By Smithson Tennant, 
Esq. F.R.S. p. 123 
V. A Supplement to the Measures of Trees , printed in the 
Philosophical Transactions for 1 759. By Robert Marsham, 
Esq. F. R. S. p. 128 
VI. On the periodical Changes of Brightness of two fixed Stars. 
By Edward Pigott, Esq. Communicated by Sir Henry C. 
Englefield, Bart. F.R.S. p. 133 
VII. Experiments and Observations , made with the View of 
ascertaining the Nature of the Gaz produced bypassing Electric 
Discharges through Water . By George Pearson, M. D. F. R. S. 
p. 142 
