370 Royal Society. 



traverses as the radius of a graduated circle, having its centre corre- 

 sponding with the place of the original object, and therefore with 

 the image to be viewed ; and the angle of aperture is measured by 

 the arc passed through between two extreme positions, in the usual 

 manner. The method is further explained in the paper by a figure 

 and description of the apparatus, which was itself exhibited in the 

 Library after the meeting. 



March 16. — Charles Wheatstone, Esq., V.P., in the Chair. 



The following paper was read : — " On some new Compounds of 

 Phenyle." By A. Williamson, Ph.D., F.C.S., Professor of Practical 

 Chemistry in University College. 



This communication contains a notice of some of the results ob- 

 tained in an investigation of Carbolic Acid or Hydrated Oxide of 

 Phenyle, conducted, under the author's superintendence, by Mr. 

 Scrugham in the Analytical Laboratory of University College. 



Referring to the substitution products obtained by Laurent from 

 hydrate of phenyle by the action of chlorine and bromine, as well as 

 to its combination with acids prepared by that chemist in conjunc- 

 tion with Gerhardt, the author states that the substance which they 

 conceived to be chloride of phenyle has been found by Mr. Scrugham 

 to be a mixture of two compounds. 



As regards the preparation of hydrate of phenyle from the creosote 

 of coal-tar, it is observed that the numerous fractional distillations 

 by which it is usually isolated may be abridged by crystallization ; 

 for if creosote, having the boiling-point between 186° and 188° Cent., 

 be left for some time in contact with a few crystals of the pure hy- 

 drate, it deposits a considerable quantity of beautiful colourless 

 needles, which, when separated from the mother-liquid, distil at 

 184° Cent., and condense in the neck of the retort into a solid mass 

 of pure hydrate of phenyle. 



When pentachlorlde of phosphorus is added to hydrate of phenyle, 

 the action is at first very energetic, hydrochloric acid being evolved, 

 and the mixture becoming hot; but after a time the addition of fresh 

 portions of pentachlorlde produces no perceptible action, unless the 

 mixture be heated. Oxychloride of phosphorus is formed, as well as 

 a neutral oily body, which is insoluble in aqueous potash at the 

 common temperature, but soluble with decomposition in boiling pot- 

 ash. This oily compound would, from its mode of formation, be 

 naturally supposed to be the chloride of phenyle, and it has been so 

 considered by some distinguished chemists. It may, however, be sepa- 

 rated by distillation into two perfectly definite and distinct bodies, one 

 of which boils at 136° Cent., the other at a temperature above the 

 range of mercurial thermometers. The former of these is a colour- 

 less mobile liquid, possessing a fragrant smell, not unlike that of 

 bitter almonds. The latter is a more consistent inodorous liquid, 

 which solidifies at a low temperature into a mass of colourless cry- 

 stals. The liquid having the boiling-point of 136° is nothing else 

 than the chloride of phenyle. The crystalline body is the phosphate of 

 phenyle, one of the most beautiful products in organic chemistry. In 

 the liquid state it is slightly yellow by transmitted light, and it re- 



