568 



THE POPULAR SCIENCE MONTHLY. 



imaginable, that of the most fashionable 

 physician in London is the last that any one, 

 however sagacious, would have predicted for 

 him. I went my way to the other side of the 

 world, for four years, in the fall of 1846, and, 

 after my return to England, the kindly fates 

 determined I should no longer be exposed to 

 the risk of committing homicide as a griev- 

 ously incompetent member of the noblest of 

 professions. So my former messmate and I 

 drifted far away from one another on our 

 several courses, and only indirect accounts of 

 him reached me from time to time. I heard 

 that destiny had withdrawn him from the 

 service, no doubt for reasons directly oppo- 

 site to those which led to my removal ; then, 

 that he was practicing in some far-off region 

 of London, eastward of the fashionable 

 Eden ; then, as it seemed quite suddenly, I 

 learned that he was a hospital physician of 

 great repute and rapidly increasing practice, 

 residing in the very omphalos of jEsculapia 

 Cavendish Square. We met now and 

 again, as busy men in London do ; but I sup- 

 pose our renewed acquaintance would have 

 stopped there, had I not fallen ill in 1871 of 

 what it was then the fashion to call over- 

 work. I was desired to rest, go to Egypt, 

 and do all sorts of other things ; which I did, 

 but with no other result than that of gradu- 

 ally descending into lower and lower circles 

 of the inferno of hypochondriacal dyspep- 

 sia. After a year or more of this increasing 

 wretchedness, a friend fairly worried me into 

 consulting the doctor who was all the fash- 

 ion, and who, I confess, seemed nowise the 

 better in my eyes for being so. It is difficult 

 for me to speak in moderate language of the 

 time and pains which one of the hardest- 

 pressed of physicians devoted to my case; 

 of his thoughtful and self-sacrificing care not 

 only of me, but of several members of my 

 family ; of the scientific sagacity of his diag- 

 nosis ; or of the firmness with which he in- 

 sisted on somewhat ascetic remedial meas- 

 ures which, in the opinion of not a few of 

 my friends, tended to speedy euthanasia. 

 Suffice it to say that I was practically well in 

 three months, and remained in a very good 

 state of repair for a dozen years. From that 

 time onward we were fast friends, none the 

 less for heartily disagreeing about a good 

 many fundamental questions. Thoughtless 

 people blame Sir Andrew Clark for not leav- 



ing off work when he had reached wealth, 

 fame, and the official headship of his profes- 

 sion. But though he may have liked these 

 rewards as well as another, my friend did 

 not live for them. His work was his life, 

 and no true friend would have desired for 

 him, of all men, a prolongation of that 

 shadow-life of enforced rest, in which there 

 is no repose." 



Action of Light on Dyes. The report of 

 the British Association's committee on the 

 action of light on dyed colors refers chiefly 

 to coloring matters belonging to groups of 

 dyes known as eosins, rosanilines, indulines, 

 and azo colors, producing various shades of 

 red. The results show that relative fastness 

 or permanence of the colors when exposed to 

 light is practically the same on silk as on 

 wool. The most fugitive red dyes are those 

 of the eosin group and their allies, while the 

 most permanent, with very few exceptions, 

 belong to the group of azo colors. One very 

 important result is that the rate of fading of 

 a dye depends mainly on its chemical consti- 

 tution, and does not depend upon whether it 

 is an artificial or a natural product. It fol- 

 lows that, contrary to the common belief, 

 artificial coloring matters are made that are 

 quite as permanent when exposed to light as 

 the colors obtained directly from vegetable 

 products. 



Guesses and Proof. Dr. Pye-Smith, in 

 the course of the last Harveian oration, de- 

 livered in London in October, said : " As 

 Paley justly puts it, ' He only discovers who 

 proves.' To hit upon the true conjecture 

 here and there amid a crowd of untrue 

 guesses, and leave it again without apprecia- 

 tion of its importance, is as a sign, not of in- 

 telligence, but of frivolity. We are told that 

 of the seven wise men of Greece one I be- 

 lieve it was Thales taught that the sun did 

 not go around the earth, but the earth 

 around the sun, and hence it has been said 

 that Thales anticipated Copernicus a fla- 

 grant example of the fallacy in question. A 

 crowd of idle philosophers, who sat through 

 the long summer days and nights of Attica 

 discussing all things in heaven and earth, 

 must sometimes have hit upon a true opin- 

 ion, if only by accident ; but Thales, or who- 

 ever broached the heliocentric dogma, had 



