the inadequate term density? Mercury at ordinary temperature is a liquid; can your scientist tell why it is not a solid? Of course anyone can say because its molecules move freely on each other. Such an answer evades the issue; why do they so readily exert this action? Copper produces green or blue salts; nickel produces green salts; have you ever been told why they observe these rules? Water solidifies at about thirty-two degrees above your so-called zero; have you ever asked an explanation of your scientific authority why it selects that temperature? Alcohol dissolves resins, water dissolves gums; have you any explanation to offer why either liquid should dissolve anything, much less exercise a preference? One species of turtle has a soft shell, another a hard shell; has your authority in natural history told you why this is so? The albumen of the egg of the hen hardens at one hundred and eighty degrees Fahrenheit; the albumen of the eggs of some turtles can not be easily coagulated by boiling the egg in pure water; why these differences? Iceland spar and dog-tooth spar are identical, both are crystallized carbonate of lime; has your mineralogist explained why this one substance selects these different forms of crystallization, or why any crystal of any substance is ever produced? Why is common salt white and charcoal black? Why does the dog lap and the calf drink? One child has black hair, another brown, a third red; why? Search your physiology for the answer and see if your learned authority can tell you why the life-current makes these distinctions? Why do the cells of the liver secrete bile, and those of the mouth saliva? Why does any cell secrete anything? A parrot can speak; what has your anatomist found in the structure of the brain, tongue, or larynx of that bird to explain why this accomplishment is not as much the birthright of the turkey? The elements that form morphine and strychnine, also make bread, one a food, the other a poison; can your chemist offer any reason for the fact that morphine and bread possess such opposite characters? The earth has one satellite, Saturn is encompassed by a ring; it is not sufficient to attempt to refer to these familiar facts; tell me, does your earth-bound astronomer explain why the ring of Saturn was selected for that planet? Why are the salts of aluminum astringent, the salts of magnesium cathartic, and the salts of arsenicum deadly poison? Ask your toxicologist, and silence will be your answer. Why will some substances absorb moisture from the air, and liquefy, while others become as dry as dust under like conditions? Why does the vapor of sulphuric ether inflame, while the vapor of chloroform is not combustible, under ordinary conditions? Oil of turpentine, oil of lemon, and oil of bergamot differ in odor, yet they are composed of the same elements, united in the same proportion; why should they possess such distinctive, individual characteristics? Further search of the chemist will explain