341 



Society's respect to one who, once my pupil, and afterwards my 

 friend, is now also my professorial brother. It is well known to 

 your early friends that it would have been easy for you, under the 

 auspices of your late father, to have soon attained a competence and 

 independence as a medical practitioner ; but you preferred the more 

 thorny path of science. I happen to know that your choice gave 

 some uneasiness and anxiety to your parent, when he reflected how, 

 few, — alas I for the scientific welfare of this country, — how very few- 

 prizes in chemical science are held out to its votaries in Britain. 

 But he was reassured by the assurance of his friends that the spark 

 so clearly visible would soon be blown into a flame ; and, accord- 

 ingly, he lived long enough to see you received by universal consent 

 among the chemists of Europe, and rewarded by the second — if, in- 

 deed, it be only the second — chemical office, in point of honour in 

 Scotland. 



I must not conclude without mentioning that the value of the 

 Keith Prize is not be measured by this medal merely. Apart from 

 the honour, the prize varies in value from £50 to £65, and the 

 latter sum is its amount on the present occasion. It is, therefore, 

 in all respects, an object well worthy of competition among scien- 

 tific men. 



The following Communications were then read : — 



1. Geometry, a science purely experimental. By Edward 



Sang. 



After remarking that the perfect strictness of the demonstrations 

 in Geometry is generally admitted, the author of the paper cited the 

 almost universal belief in the soundness of Euclid's reasoning as a 

 notablie example of wide-spread credulity. He then enunciated the 

 proposition that our knowledge of the truths of geometry is alto- 

 gether derived from experience. 



Taking the first of Euclid's problems, "To construct an equilateral 

 trigon," he showed that the facts that the circles intersect at all, 

 and that they have only one intersection on each side of the base, are 

 taken for granted, and he contrasted the looseness of this procedure 

 with the hypercritical precision of the following problem " to cut 

 from the greater of two lines a part equal to the less." 



VOL. III. 2 E 



