21 8 THE POPULAR SCIENCE MONTHLY. 



builds the ricks. Science has thus greatly reduced the actual cost of 

 labor, and yet it has increased the wages of the laborer. 



It was to the British Association, at Glasgow, in 1841, that Baron 

 Liebig first communicated his work " On the Application of Chemis- 

 try to Vegetable Physiology," while we have also from time to time 

 received accounts of the persevering and important experiments which 

 Mr. Lawes, with the assistance of Dr. Gilbert, has now carried on for 

 more than forty years at Rothamsted, and which have given so great 

 an impulse to agriculture by directing attention to the principles of 

 cropping, and by leading to the more philosophical application of 

 manures. 



I feel that, in quitting Section F so soon, I owe an apology to our 

 fellow- workers in that branch of science, but I doubt not that my short- 

 comings will be more than made up for by the address of their excel- 

 lent President, Mr. Grant-Duff, whose appointment to the governor- 

 ship of Madras, while occasioning so sad a loss to his friends, will un- 

 questionably prove a great advantage to India, and materially conduce 

 to the progress of science in that country. 



Moreover, several other subjects of much importance, which might 

 have been referred to in connection with these latter sections, I have 

 already dealt with under their more purely scientific aspect. 



Indeed, one very marked feature in modern discovery is the man- 

 ner in which distinct branches of science have thrown, and are throw- 

 ing, light on one another. Thus the study of geographical distribution 

 of living beings, to the knowledge of which our late general secretary, 

 Mr. Sclater, has so greatly contributed, has done much to illustrate an- 

 cient geography. The existence of high northern forms in the Pyre- 

 nees and Alps points to the existence of a period of cold when Arctic 

 species occupied the whole of habitable Eui'ope. Wallace's line as it 

 has been justly named after that distinguished naturalist points to 

 the very ancient separation between the Malayan and Australian re- 

 gions ; and the study of corals has thown light upon the nature and 

 significance of atolls and barrier-reefs. 



In studying the antiquity of man, the archaeologist has to invoke 

 the aid of the chemist, the geologist, the physicist, and the mathemati- 

 cian. The recent progress in astronomy is greatly due to physics and 

 chemistry. In geology the composition of rocks is a question of chem- 

 istry ; the determination of the boundaries of the different formations 

 falls within the limits of geography ; while paleontology is the biol- 

 ogy of the past. 



And now I must conclude. I fear I ought to apologize to you for 

 keeping you so long, but still more strongly do I wish to express my re- 

 gret that there are almost innumerable researches of great interest and 

 importance which fall within the last fifty years (many even among 

 those with which our Association has been connected) to which I have 



