PHYSICAL SCIENCE. 7 



and scope of physical science to which we have just alluded. 

 In the first of these Essays, Mr. Powell describes the doc- 

 trines he advocates under the titles of f Unity of Sciences,' 

 and f Uniformity of Nature,' terms meant to express, but 

 expressing too strongly, those admirable generalisations which 

 have connected under common laws phenomena seemingly 

 the most remote and unlike, and are continually tending 

 still further so to connect them. Taking the subject in this 

 general sense, we cannot hesitate to regard it as one of the 

 very highest which can be submitted to the human under- 

 standing. The unfulfilled objects of science, as well as its 

 ultimate end and aim, evidently lie in this direction; and 

 none can be indifferent to the wonderful results which every 

 year is disclosing to researches pursued on this principle. 

 Among those who have laboured most successfully for this 

 especial object are the eminent men whose discoveries in 

 particular branches of science have given them merited fame 

 in the world. If out of many contemporaries we were to 

 select a few who have done most to elevate physical science 

 by generalisation of its phenomena and laws, the names of 

 Arago, Faraday, Herschel, and Humboldt occur at once as 

 first in this career. These philosophers have looked upon 

 the world of nature in its largest aspects, and made their 

 several discoveries subservient to this great object ; thereby 

 widening the circle of facts and phenomena, and at the same 

 time drawing them more closely towards that centre in which 

 we find so many sciences to converge. 



Nevertheless we must not allow these terms of f Unity of 

 Science,' ( Unity of Principle,' and c Unity of Law,' to usurp 

 too much on the understanding. Professor Powell gives 

 undue force to such phrases ; which, strictly examined, have 

 no reality in our actual knowledge. It is true that there is 

 various high authority for their use, as for that of language 

 analogous in effect. Humboldt, in several passages of his 



