Royal Society. 53 



esccnt state is less than had been previously estimated, and that the 

 ordinary atmospheric resistance in railway progression arises from 

 the air being generally itself in motion, and as the direction of the 

 current is almost always oblique, from its producing increased fric- 

 tion in the carriages themselves. This kind of resistance will not 

 increase as the square of the velocity; and as it is the principal one, 

 it follows that the resistance to railway trains increases in a ratio 

 not much higher than the velocity, and that the practical limit to the 

 speed of railway travelling is a question, not of force, but of safety. 



March 26. — " On the Muscularity of the Iris." By Professor 

 Maunoir, of Geneva. Communicated by P.M. Roget, M.D., Sec.R.S. 



The author has satisfied himself, from the result of his own dis- 

 sections, as well as from the concurrent testimony of a great number 

 of anatomists, that the iris is provided with two sets of muscular 

 fibres, the one orbicular, immediately surrounding the pupillary 

 margin and acting as a sphincter; the other, extending in a radiated 

 direction from the exterior circumference of the former to their in- 

 sertions into the ciliary ligament, their action being to enlarge the 

 pupil. One-fourth of the disc of the iris is occupied by the orbi- 

 cular, and the remaining three-fourths by the radiated muscle. The 

 author has examined the structure of the iris in a great number of 

 animals, and states the results obtained by M. Lebert, whom he 

 applied to on this occasion, from numerous dissections of the eyes 

 of animals belonging to each class of vertebrata. He also refers to 

 a work which he published in the year 1812, entitled " Memoire sur 

 l'Organisation de lTris," for evidence of the muscularity of the iris 

 which he obtained by applying galvanism to the human eye imme- 

 diately after decapitation ; and he concludes with the narrative of 

 the case of a wcman in whose iris there had been formed, by an 

 accidental wound with the point of a knife, a triangular aperture 

 below the pupil. This aperture became dilated when the pupil was 

 contracted, and vice versa ; thus furnishing a proof that its move- 

 ments were effected by muscular action. 



April 2. — Contributions to the Chemistry of the Urine. Part II. 

 " On the Variations in the Alkaline and Earthy Phosphates in Dis- 

 ease." By Henry Bence Jones, M.D., Fellow of the Royal College 

 of Physicians. Communicated by Thomas Graham, Esq., F.R.S., &c. 



The analyses, of which the results are given in a series of tables, 

 were made by the author, chiefly from the urine of patients labour- 

 ing under different diseases in St. George's Hospital, and therefore 

 nearly under the same circumstances as far as exercise was con- 

 cerned. He found that the variations in the earthy phosphates were 

 in general independent of the nature of the disease. In fractures of 

 the spine and paraplegia, however, the total amount of these salts 

 was slightly above the healthy standard during the early period, 

 and when inflammatory action might be considered as prevailing ; 

 but when this action had subsided, and the affection had become 

 chronic, the total quantity of phosphatic salts was less than natural. 

 In chronic diseases of the brain, and in chronic and even in acute 

 diseases of the membranes, no increase of these salts was observed. 



