256 



ceeded to give a detailed description of Cologne Cathedral, 

 as the best specimen of Gothic architecture in the world, 

 and illustrating in itself all the principles of the style. He 

 illustrated his description by a series of magnificent engrav- 

 ings of this cathedral. This edifice was begun in 1248 and 

 progressed till 1460, when owing to political dissensions it 

 was abandoned. Recently, through the efforts of the pre- 

 sent architect, the work has been resumed, and it is esti- 

 mated that about fifty or sixty years more may suffice to 

 complete it. 



At the close of M. von Steinwehr's paper, Mr. Gavit stated 

 some interesting details as to the energy and enthusiasm of 

 the present architect, and the difficulties he had overcome 

 in recovering the details of the original plan on which the 

 structure had been begun. 



Mr. Paterson gave a history of the problem proposed at 

 the last meeting of the Institute, the various solutions which 

 have been given of it by different mathematicians, and 

 finally gave a solution of his own. 



Prof. Murray presented the solution which had been sent 

 in by Mr. Ebenezer Mix, who had proposed the problem to 

 the Institute. 



Dr. Gould gave some account of the processes which had 

 been in use for determiuing the physical constants of the 

 Dudley Observatory, and the results thus far obtained. 

 After alluding to the importance of investigating the phy- 

 sical characteristics of places on the surface of the earth at 

 which delicate observations are to be made, and of sparing 

 no effort to secure the greatest accuracy, he proceeded to 

 describe the instruments and processes which had been 

 employed for the determination of the direction and inten- 

 sity of terrestrial magnetism at the observatory. 



These observations gave : 



Declination, 8° 17'. with probable error 0'.17. 



Diurnal motion of needle, 13'. 9 at mean temp. 15° cent. 



Dip of needle, 74° 56'.6, probable error 0'.49. 



