Masterpieces of Science 



stimulating effects, we shall be reminded of a 

 series of permutations where the latest of the 

 factors, because latest, multiplies all prior factors 

 in an unexampled degree.* We shall find reason 

 to believe that this is not merely a suggestive 

 analogy, but really true as a tendency, not only 

 with regard to man's gains by the conquest of 

 electricity, but also .with respect to every other 

 signal victory which has brought him to his 

 present pinnacle of discernment and rule. If 

 this permutative principle in former advances 

 lay undetected, it stands forth clearly in that 

 latest accession to skill and interpretation which 

 has been ushered in by Franklin and Volta, 

 Faraday and Henry. 



Although of much less moment than the 

 triumphs of the electrician, the discovery of 

 photography ranks second in importance among 

 the scientific feats of the nineteenth century. 

 The camera is an artificial eye with almost every 

 power of the human retina,* and with many that 



* Permutations are the various ways in which two or 

 more different things may be arranged in a row, all the things 

 appearing in each row. Permutations are readily illus- 

 trated with squares or cubes of different colours, with num- 

 bers, or letters. 



Permutations of two elements, i and 2, are (1x2) two; 

 i, 2; 2, i ; or a, b; b, a. Of three elements the permutations 

 are (i x 2 x 3) six; i, 2, 3; i, 3, 2; 2, i, 3; 2, 3, i ; 3, i, 2, 3, 2, i; 

 or a, b, c; a, c, b; b, a, c;, b, c, a; c, a, b; c, b, a. Of four ele- 

 ments the permutations are (1x2x3x4) twenty-f oxtr ; 

 of five elements, one hundred and twenty, and so on. A 

 new element or permutator multiplies by an increasing 

 figure all the permutations it finds. 



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