196 Evolution of the Mechanic Arts. 



through changes of the subjective order and developing 

 faculty in man, interesting as it might be to do so. But, 

 being germane to our subject, we should notice the relations 

 of mechanisms to man in his system of psychology. He 

 says : " All observing instruments, all weights, measures, 

 scales, micrometers, verniers, microscopes, thermometers, 

 etc., are artificial extensions of the senses; and all levers, 

 screws, hammers, wedges, wheels, latht s, etc., are artificial 

 extensions of the limbs. The magnifying glass adds but 

 another lense to the lenses existing in the eye. The crow- 

 bar is but one more lever attached to the series of levers 

 forming the arm and hand. And the relationship which is 

 so obvious in these first steps, holds throughout. This 

 being perceived, a meaning becomes manifest in the fact 

 that the development of these supplementary senses is de- 

 pendent on the development of these supplementary limbs, 

 and vice versa." (Frin. of Fsy., p. 365.) 



Romanes, in his diagram, places carnivora, rodents and 

 ruminants at Ko. 2Q in the ascending scale of animal devel- 

 opment, opposite No. 26 in the scale of products of intel- 

 lectual development, which is stated to be " Understanding 

 of mechanisms " ; monkeys and elephants at No. 27, oppo- 

 site to No. 27 in corresponding scale, "Use of tools"; 

 and birds at No. 25, corresponding to which is '' Recognition 

 of pictures. Understanding of words. Dreaming"; and he 

 thus scales the highest capacities of each. My own birds 

 I see every day showing understanding of mechanisms, or 

 qualifications for the grade of No. 26, one grade above that 

 allotted them by Romanes. 



Dealing with the root principles of mind and the "cor- 

 relations between muscular and mental evolution," Romanes 

 says : " The wonderful intelligence of the Elephant may be 

 safely considered as correlated with the no less wonderfid 

 instrument of co-ordinated movement wliich he possesses 

 in his trunk ; while the superior intelligence of the Monkey, 

 and the suprevie intelligence of Man may be no less safely 

 considered as correlated with the still more wonderful in- 

 strument of co-ordinated movement which has attained to 

 almost ideal perfection in the human hand.". . . "Tims 

 the two faculties are, as it were, necessarily bound together. 

 Biit here another consideration arises. They are thus 

 bound together only up to the ])oint at which the adajitive 

 movements are dependent upon the machinery supplied by 



