1869.] Dr. H. E. Roscoe's Researches on Vanadium. 



37 



of the position of the postauricular depression, in both vertical and hori- 

 zontal direction, as compared with the front of the foramen magnum. 

 That position varies in different races, and is affected by gravitation changes. 



10. The position of greatest breadth varies according to the time of life, 

 and as the spaces adjacent to the mesial and lateral roof-ridges are well 

 filled or ill filled ; and an hypothesis is advanced in explanation of this, and 

 of the mesial ridge being prominent in savage skulls, although the ridge 

 on the fcetal skull disappears in childhood. 



1 1 . Orthognathism and prognathism are shown to be concrete results of 

 a variety of circumstances, some of them not connected with the anatomy 

 of the face, as, for example, the degree of cranial curvature. The extent to 

 which the face projects from underneath the skull must be measured by an 

 angle contained between the fore part of the face and the floor of the 

 anterior fossa only of the skull, the curves of the base of the skull further 

 back having really nothing to do with the matter. This projection of the 

 face is great in French skulls, considerable in Scotch, and small in Irish and 

 German skulls. 



12. The facial angle is affected by the height of the ear above the 

 foramen magnum, while prognathism is not. 



13. The condyles of the skull become more and more prominent in front 

 from infancy to adult life, and thus tilt the skull more and more back- 

 wards. By this rotation balance is preserved, seeing that the fore part of 

 the head and the face are the parts which proportionally increase in size 

 as growth proceeds, and their increased proportion of weight is made up 

 for by a greater amount being thrown behind the vertebral column. There 

 is less tilting back in the female head than the male. 



14. This principle is shown to be most important in Artistic Anatomy. 



15. In the lower animals the cerebral curvature is of very different 

 amount in different species, the most advanced animals having it greatest. 



XIX. " Researches on Vanadium." — Part II. By Henry E. Roscoe, 

 B.A., Ph.D., F.R.S. Received June 16. Read June 17, 1869. 



(Abstract.) 



On the Chlorides of Vanadium and Metallic Vanadium 



In the first part of these researches (' Bakeriau Lecture,' Phil. Trans. 

 1868, pt. i.) the author stated that the chlorides of vanadium, and pro- 

 bably also the metal itself, could be prepared from the mononitride, the 

 only compound of vanadium not containing oxygen then known. The 

 process for obtaining the mononitride described in the last communication 

 was that adopted by Berzelius for preparing the substance which he con- 

 ceived to be metal, but which in reality is mononitride. This method 

 consists in the action of ammonia on the oxitri-chloride; but it cannot be 



