KNOWLEDGE & SCIEXTIEIC NEWS. 



I June, 1905. 



complex compounds containing carbon, hydrogen, 

 oxygen, and nitrogen — namely, the proteids. We find 

 that thev are almost invariably characterised by their 

 feeble stability, and have undoubtedly a comparatively 

 low critical temperature of decomposition. So feeble, 

 indeed, is the general affinity of carbon for hydrogen, 

 oxygen, and nitrogen, that at a red heat the whole of 

 organic chemistry is destroyed. 



From the facts discussed in my work, " Researches 

 on the Affinities of the Elements," chap. II., pp. 120- 

 123, it is probable that such a compound would have 

 definite physical characters. For since its atoms at- 

 tract each other but feebly, the molecules would also 

 attract each other but feebly. It would, therefore, be 

 either of a fl.iid or semi-fluid nature, and soft. Be- 

 cause its molecules are very great it would not be 

 volatile. Does such a compound exist? I believe so, 

 the compound being nothing more nor less than the 

 protoplasm v.hich forms the basis of living matter. 

 All its chemical and physical characteristics agree with 

 what we should have expected. It is formed out of the 

 four elements, carbon, hydrogen, oxygen, and nitrogen, 

 with small amounts of phosphorus and sulphur; it is of 

 a semi-fluid and soft nature; it is in a state of continual 

 and intermittent change so long as life continues; the 

 temperature of living matter keeps remarkably con- 

 stant, precisely as it should do on our supposition — a 

 temperature too high exceeding its critical temperature 

 of decomposition and thus destroying its structure, 

 while a temperature too low causes it to cease to de- 

 compose and the living matter becomes inactive. 



The temperalure range of animal life, then, is probably 

 nothing mere nor less than the range of the critical tem- 

 peratures cf decomposition of a certain series of very 

 complex carbon compounds grouped together under the 

 name ' ' protoplasm. ' ' The external pressure of the 

 atmosphere coincides roughly with the critical pressures of 

 decomposition. 



The incessant varying in the external conditions of 

 temperature and pressure, and the external influences, 

 such as radiation and light, which are continually beat- 

 ing upon the earth from external space, are thus the 

 cause of the continuous change characteristic of living 

 matter. In fact, just as a tuning fork is set into motion 

 by vibrations of a certain definite frequency, and by no 

 others, so living matter is so constructed as to respond 

 continuously to the incessant minute fluctuations in 

 the external conditions which hold upon the earth, the 

 state of response being what is known as life. 



The difference in the functioning of the different parts 

 of the protoplasm (which exhibits itself in the tendency 

 to produce different organs) is probably due to the 

 different sensitiveness of the different sorts of proto- 

 plasm to different specific external influences. .Such a 

 differentiation in the nature of the protoplasm in the 

 different organs is probably brought about by the sub- 

 stitution of minute quantities of light or heavy elements 

 for the other elements in its structure. Such a sub- 

 stitution alters to a slight extent the critical tempera- 

 ture of decomposition of the protoplasm, and thus 

 makes it more or less sensitive to certain specific ex- 

 ternal influences according to specific needs. This 

 probably explains why certain specific heavy elements 

 are retained in considerable quantities in certain organs, 

 and are almost entirely absent from other organs. The 

 different modes of action of the protoplasm are thus 

 probably due solely to the different critical temperatures 

 and pressures of certain parts of the protoplasm. 

 (7'o he continuid ) 



The ConservsLtion of 



MSlSS. 



By Alfred W. Porter, B.Sc. 



Fellow of, and Assistant Professor of Physics in, University 



College, London. 



{Continued from December, 1 904.) 

 IL 



Ls the first part emphasis was placed on the fact that an 

 ordinary balance compares two forces witli one another — 

 viz., the u'ciglits of two bodies — and that the weight of a 

 body is not a satisfactory measure of the amount of stufT 

 in it, because the weight varies from place to place. We 

 further defined another quantity — the mass of the body — 

 which was asserted to be a constant for the same body 

 under all conditions. It is our intention now to show 

 that a relation exists between these quantities. For, in 

 fact, the weight of a body is only another term for the 

 action between the body and the earth. These are two 

 bodies which change each other's motion by their mutual 

 influence. The motion of the earth produced by a falling 

 stone is, indeed, too small to be directly observed; and, 

 moreover, as we are on the earth, and move with it, it 

 would in any case be liable to escape our observation. 

 ISut we nevertheless do not doubt that this case falls in 

 with the general rule that every action is accompanied 

 by an equal but opposite reaction. 



If we take this for granted, we may write clown an 

 equation for the earth and stone similar to that between 

 the inter-acting billiard balls : — 



Mass of stone increase in velocity of earth. 

 Mass of earth ~ decrease in velocity ot stone. 



The time during which the change is observed may be 

 any whatever ; but it will be most convenient to refer to 

 the changes in velocity that take place in unit time — 

 that is, to the rate of increase, which is called the accelera- 

 tion. Denoting the masses of stone and earth by the 

 letters m and E, and the accelerations by a and g, the 

 equation becomes 



m a 



'^ ^ " S 

 which may be written 



ing = — E(j. 



It is this product which measures the action between 

 the two bodies ; nig is the action of the earth on the 

 stone — i.e., its u'eight — whereas — Ma is the opposite and 

 equal reaction of the stone on the earth. The connection 

 betweenjwi^/i/and niassis that the former is the latter mul- 

 tiplied by g (the acceleration while falling freely). Now 

 all experiment goes to show that when disturbing causes 

 are eliminated, all bodies have the same acceleration in 

 the same locality ; so that with this restriction as to 

 locality, weight and mass are proportional to one 

 another. On the other hand, the relation between the 

 two is difTerent even for the same body when the locality 

 is changed. For the sake of clearness think of one body 

 alone. In any particular locality it has a certain weight, 

 a certain mass, and a definite acceleration under the 

 action of the earth's pull. In another locality it con- 

 ceivably has a different weight, mass, and acceleration. 

 In each locality these three quantities are not indepen- 

 dent of one another, but are related by the etjuation — 

 Weight = mass x g. 



And the important question to which an answer must 

 be given is — Can we account for the variation in weight 

 by the variation in g alone, without supposing the mass 

 to vary, or is the mass also subject to variation ? 



