94. 



which he could only explain by referring them to parallax. Among 

 these stars, a Aquilae exhibited the greatest change of place. 



In consequence of the Astronomer Royal having doubted the cor- 

 rectness of the author's conclusions upon this point, he has anxiously 

 engaged in observations relating to it during the last sixteen months; 

 and although the results in respect to a Lyrae and to Arcturus have 

 not been very uniform, the recent observations on a Cygni are consis- 

 tent with the former ones, and exhibit the same discordance between 

 the summer and winter observations as before. In regard to a Aquilae 

 also, the observations detailed in the present paper are remarkably 

 coincident with those formerly detailed ; and the author thinks that 

 it is to this star we must look for the final decision of the question 

 concerning parallax. 



Referring to Mr. Pond's observations, Dr. Brinkley is led to enter- 

 tain doubts of the fitness of an instrument similar to the Greenwich 

 mural circle for so delicate an inquiry, founded upon remarks detailed 

 in the paper respecting the elements used in computing the index 

 error, and which are independent of the uncertainties to which the ob- 

 servation itself is also subject. It is, however, from the uncertainty 

 of the elements used in the reductions, and not from any errors of the 

 observations, or from any defect in the construction of the instrument 

 alluded to, that Dr. Brinkley is induced to consider the observations 

 hitherto made at Greenwich as not affording conclusive results as to 

 the existence or non-existence of parallax. In the present state of 

 astronony, however, it will be allowed that the relative fitness of 

 instruments for ascertaining with precision the smaller motions, 

 whether real or apparent, of the fixed stars, is an object of import- 



On the Urinary Organs and Secretions of some of the Amphibia. By 

 John Davy, M.D. F.R.S. Communicated by the Society for the 

 Improvement of Animal Chemistry. Read April 2, 1818. [Phil. 

 Trans. 1818,^.303.] 



In several species of serpents which were examined by Dr. Davy, 

 the kidneys were nearly as large as the liver, long, narrow and lobu- 

 lated, and without a pelvis. Each lobule sends a small duct to the 

 ureter, which terminates in a papilla situated in the cloaca, between 

 the mouths of the oviducts, and having its point directed towards a 

 receptacle for the urine, which, though a continuation of the intes- 

 tine, may be considered as distinct from the rectum and cloaca, with 

 which it communicates only by sphincter orifices. 



The urinary ducts often contain a white matter, visible through 

 their coats, which gradually accumulates in the receptacle till it 

 forms a mass which, when of so large a size as to distend the part, 

 is usually expelled by an extraordinary effort of the animal, most 

 commonly in the act of devouring its food. The urine, at first soft, 

 gradually hardens by exposure, and then looks like chalk ; it consists 

 of nearly pure uric acid. 



