122 MEETING OF THE BRITISH ASSOCIATION. 



principles that we ever had the good fortune to hear, amid the loud- 

 est plaudits of the highly respectable crowd which filled the room.] 



Wediicsdaif. — At nine o'clock the College of Surgeons entertained 

 the distinguished strangers at their splendid College, in Stephen's- 

 green. The Library, Examination-Hall, and Museum, were thrown 

 open as reception rooms, and the dejeune was laid out in the Board- 

 room, Committee-rooms, and other apartments, in this magnificent 

 building. About six hundred persons were present, and so admi- 

 rable were the arrangements, that not a wish or want of any of 

 the numerous persons assembled was left ungratified. Mr. Read, 

 the president of the College of Surgeons, who presided, was unre- 

 mitting in his attentions, and unceasing in his exertions. After the 

 dejeune all the rooms in the College were thrown open for inspec- 

 tion. Shortly before eleven o'clock the members had retired to the 

 various sectional meetings. 



Section A. — Mnthematics and Physics. — The first paper read 

 was the continuation of Mr. Snow Harris's highly interesting ob- 

 servations on the use of the proof-plane of Coulomb. Capt. Sa- 

 bin explained Hanstein's theory of the earth's magnetic curves ; and 

 attributed the difference observed in the polenity and dip of the com- 

 pass needle, in different places, to the existence of two northern and 

 two southern magnetic poles to the earth. — Professor Wheatstone 

 read an account of his experiments on the decomposition of the light 

 of the electrical spark, produced by different means. — Mr. Fox ex- 

 hibited his improved needle, for observing the dip and intensity of 

 the earth's magnetism at difierent places. The instrument and ex- 

 planation appeared to give much satisfaction. The Rev. Mr. 



M'^Gauley explained his electro-magnetic machine for producing mo- 

 tion, and stated the prospect which was being opened of converting 

 the power of electro-magnets to useful purposes. He also detailed 

 a number of experiments to illustrate the nature of electro-magnetic 

 induction. The novelty and great ingenuity of Mr. M^Gauley's 

 views, and their application, excited the greatest admiration. — Pro- 

 fessor Hamilton next made a communication on the nature of alge- 

 bra, which he defined '" to be the science of pure time, as geometry 

 is the science of pure space." He referred to a paper in the last 

 number of the Transactions of the Irish Academy, which contained 

 his suggestions for certain improvements and simplifications in al- 

 gebra. 



Section B. — Chemistry and Mineralogy. — Mr. Mallet, of Dub- 

 lin, read a very valuable paper on a peculiar alteration which 

 takes place in the flame of coal-gas by the introduction of air, by 

 means of concealed tubes introduced to the air passage of the ar- 

 gand burner usually employed ; the gas burns with a blue flame, 

 yielding no light, and returns downward upon the blast. Mr. Mallet 

 did not attempt to account for the effect so produced. The reading 

 of this paper gave rise to several observations on oil and coal gases. 

 Mr. Connell read a paper on fossil scales, and, from an analysis of 

 them, suggested the means of discovering whether they were those 



