536 [April 30, 



IV. " On the Arrangement of the Muscular Fibres of the Ven- 

 tricular Portion of the Vertebrate Heart ; with Physiological 

 Remarks/' By JAMES PETTIGREW, M.D. Communicated 

 by Professor GOODSIR. Received March 26, 1863. 



This paper is a revised version of a previous one, having the 

 same title, which was communicated to the Society on the 22nd of 

 November, 1859, and formed the substance of the Croonian Lec- 

 ture delivered by the author on the 19th of April, 1860. 



The author has now included the results of his researches on the 

 structure of the ventricular portion of the heart in fishes, reptiles, 

 and birds. 



April 30, 1863. 

 Major-General SABINE, President, in the Chair. 



Pursuant to notice given at the last Meeting, Professor Heinrich 

 Gustav Magnus, of Berlin, was balloted for, and elected a Foreign 

 Member of the Society. 



The following communications were read : 



I. " On Spectrum Analysis ; with a Description of a large 

 Spectroscope having nine Prisms, and Achromatic Telescopes 

 of two-feet focal power." By JOHN P. GASSIOT, F.R.S. 

 Received April 21, 1863. 



(Abstract.) 



The author, after briefly alluding to the discoveries of Fox 

 Talbot, Wheatstone, Foucault, Kirchhoff, and Bunsen, and the im- 

 portance of spectrum analysis, states that among the numerous 

 spectroscopes which were exhibited in the International Exhibition 

 of 1862, there was one which had been specially constructed by 

 Messrs. Spencer, Browning, and Co., philosophical instrument 

 makers in London, which at the time excited considerable attention. 

 This spectroscope had two prisms, with a magnifying power of 40, 

 its definition being remarkably clear. 



