102 



CHEMISTEY. 



gree, tlie number expressing the rate is to be multi- 

 plied by a constant quantity. 



Tyndall on Molecular Force. Professor 

 Tyndall, in an address delivered before the 

 Mathematical and Physical Science section of 

 the British Association in August, 1868, made 

 the following suggestive remarks : 



Every particle that enters into the composition of 

 the muscle, a nerve, or a bone, has been placed in its 

 position by molecular force. And unless the exist- 

 ence of law in these matters be denied, and the ele- 

 ment of caprice be introduced, we must conclude 

 that, given the relation of any molecule of the body 

 to its environment, its position in the body might be 

 predicted. Our difficulty is not with the quality of 

 the problem, but with its complexity ; and this diffi- 

 culty might be met by the simple expansion of the 

 faculties which man now possesses. Given this ex- 

 pansion, and given the necessary molecular data, and 

 the chick might be deduced as rigorously and as 

 logically from the egg as the existence of Neptune 

 was deduced from the disturbances of Uranus, or as 

 conical refraction was deduced from the undulatory 

 theory of light. 



You see I am not mincing matters, but avowing 

 nakedly what many scientific thinkers more or less 

 distinctly believe. The formation of a crystal, a 

 plant, or an animal, is in their eyes a purely mechan- 

 ical problem, which differs from the problems of or- 

 dinary mechanics in the smallness of the masses and 

 the complexity of the processes involved. Here you 

 have one half of our dual truth ; let us now glance at 

 the other half. Associated with this wonderful 

 mechanism of the animal body, we have phenomena 

 no less certain than those of physics, but between 

 which and the mechanism we discern no necessary 

 connection. A man, for example, can say, " I feel, 1 

 think, I love ; " but how does consciousness infuse it- 

 self into the problem ? The human brain is said to be 

 the organ of thought and feeling : when we are hurt, 

 the brain feels it ; when we ponder, it is the brain 

 that thinks ; when our passions or affections are ex- 

 cited, it is through the instrumentality of the brain. 

 Let us endeavor to be a little more precise here. I 

 hardly imagine that any profound scientific thinker 

 who has^ reflected upon the subject exists, who would 

 not admit the extreme probability of the hypothesis, 

 that for every fact of consciousness, whether in the 

 domain of sense, of thought, or of emotion, a certain 

 definite molecular condition is set up in the brain 5 

 that this relation of physics to consciousness is inva- 

 riable, so that, given the state of the brain, the 

 corresponding thought or feeling might be inferred ; 

 or, given the thought or feeling, the corresponding 

 state of the brain might be inferred. But how in- 

 ferred ? It is at bottom not a case of logical inference 

 at all, but of empirical association. You may reply 

 that many of the inferences of science are of this 

 character ; the inference, for example, that an electric 

 current of a given direction will deflect a magnetic 

 needle in a definite way ; but the cases differ in this, 

 that the passage from the current to the needle, if not 

 demonstrable, is thinkable, -and that we entertain no 

 doubt as to the final mechanical solution of the prob- 

 lem ; but the passage from the physics of the brain 

 to the corresponding facts of consciousness is un- 

 thinkable. Granted that a definite thought and a 

 letimte molecular action in the brain occur simulta- 

 neously, we do not possess the intellectual organ, nor, 

 apparently, any rudiment of the organ, which would 

 enable us to pass by a process of reasoning from the 

 one phenomenon to the other. They appear together, 

 but we do not know why. Were our minds and 

 senses so expanded, strengthened, and illuminated 

 as to enable us to see and feel the very molecules of 

 the brain ; were we capable of following all their mo- 

 tions, alltheir groupings, all their electnc discharges, 

 if such there be ; and were we intimately acquainted 



with the corresponding states of thought and feeling, 

 we should be as far as ever from the solution of the 

 problem, " How are these physical processes con- 

 nected with the facts of consciousness ? ' ' The chasm 

 between the two classes of phenomena would still re- 

 main intellectually impassable. Let the conscious- 

 ness of love, for example, be associated with a right- 

 handed spiral motion of the molecules of the brain, 

 and the consciousness of hate with a left-handed spi- 

 ral motion. We should then know when we love 

 that the motion is in one direction, and when we 

 hate that the motion is in the other ; but the " why ? " 

 would still remain unanswered. 



In affirming that the growth of the body is me- 

 chanical, and that thought, as exercised by us, has 

 its correlative in the physics of the brain, I think the 

 position of the " Materialist" is stated as far as that 

 position is a tenable one. I think the materialist 

 will be able finally to maintain this position against 

 all attacks ; but I do not think, as the human mind 

 is at present constituted, that he can pass beyond it. 

 I do not think he is entitled to say that his molecu- 

 lar groupings and his molecular motions explain 

 everything. In reality they explain nothing. The 

 utmost he can affirm is the association of two classes 

 of phenomena of whose real bond of union he is in 

 absolute ignorance. The problem of the connection 

 of the body and soul is as insoluble in its modern 

 form as it was in the pre-scientific ages. Phospho- 

 rus is known to enter into the composition of the hu- 

 man brain, and a courageous writer has exclaimed, 

 in his trenchant German, ." Ohne phosphor kein ge- 

 danke." That may or may not oe the case ; but 

 even if we knew it to be the case, the knowledge 

 would not lighten our darkness. On both sides of 

 the zone here assigned to the materialist he is equally 

 helpless. If you ask him whence is this " matter" 

 of which we have been discoursing, who or what di- 

 vided it into molecules, who or what impressed upon 

 them this necessity of running into organic forms, 

 he has no answer. Science also is mute in reply to 

 these questions. But if the materialist is confounded, 

 and science rendered dumb, who else is entitled to 

 answer ? To whom has the secret been revealed ? 

 Let us lower our heads, and acknowledge our igno- 

 rance, one and all. Perhaps the mystery may resolve 

 itself into knowledge at some future day. 



Action of Light. Professor Tyndall has 

 communicated to the Royal Society the results 

 of experiments made by subjecting the vapors 

 of volatile liquids to the action of concen- 

 trated solar or electric light. A tube 2.8 

 feet long, and 2.5 inches internal diameter, 

 is closed at both ends by glass plates. It may 

 be connected with an air-pump, and with a 

 series of tubes used for the purification of 

 air. A number of test-tubes were converted 

 into Wolf's bottles by means of corks and 

 tubes. Each test-tube was partly filled with 

 the liquid to be examined and introduced into 

 the path of the purified air. When the experi- 

 mental tube was exhausted, and the air then 

 allowed to bubble through the liquid, a mix- 

 ture of air and vapor entered the experimental 

 tube together, and was then submitted to the 

 action of light. At one end of the experi- 

 mental tube was placed an electric lamp trans- 

 mitting an intense beam of light through the 

 tube parallel to its axis. When the vapor of 

 amylic nitrite was allowed to enter the tube in 

 the dark, and the beam of light was then sent 

 through the tube, the tube appeared for an 

 instant optically empty ; then a sudden shower 

 of liquid spherules was precipitated on the 



