NOVBMBEB 30, 1900.] 



SCIENCE. 



827 



position, says Richter, has already in the 

 case of four quantitative series been raised 

 to the dignity of an incontrovertible rule. 

 The tables of masses form arithmetical pro- 

 gressions and the afiSnities of the elements 

 which belong to the series, proceed also, in 

 so far as they are not disturbed by the in- 

 dwelling elementary fire, in the order of 

 the masses. Besides one is in position to 

 Bee the probability of many homogeneous 

 elements present in nature. Also the 

 doubled affinities proceed in arithmetical 

 progression and with careful observations 

 one can scarce resist the thought that the 

 entire chemical system consists of similar pro- 

 gressions. 



It is well to examine a series given by 

 Eichter to get more fully at his meaning. 

 Thus in the same volume, page 28, he gives 

 the masses of the alkaline earths which 

 neutralize 1,000 parts of hydrochloric acid. 



Magnesia 734 = a 



Lime 858 = a + 6 ( 734 + 124J = 858 J) 



Alumina 1,107 = a + 3b (734 + 3 X 124J = l,107i) 

 = a + 5b (734 + 5 X 124} = 1,356J) 

 = a + n (734 + 5X124J = l,605J), 

 etc. 



Baryta 3, 099 = a + 19J ( 734 -j- 19 X 124} = 3, 099} ) 



Similar series are given for the alkalies 

 and alkaline earths with the different acids. 

 Again these tables are compared with one 

 another and thus was brought out the law 

 of proportionality. One of the most re- 

 markable regularities is obtained by exam- 

 ining the differences in the masses in such a 

 series made up of observed combining num- 

 bers of known elements and interpolated 

 combining numbers of hypothetical ele- 

 ments. Thus (p. 38) : 



616 — 526 = 90 =1X90 

 796 — 526 = 270 = 3 X 90 

 973 — 526 = 447 = 5 X 90 — 3 

 1,152 — 526 = 626 = 7 X 90 — 4 

 1,330 — 526 = 804 = 9 X 90 — 6 

 etc., etc. 



Of course, it is readily seen that all 

 these regularities are more in the line of 



the triads of Dobereiner or the later work 

 of Dumas than the periodic system. But . 

 a close examination reveals something more 

 — a really deeper insight into the nature of 

 the elements which is marvellous when 

 one considers that Eichter was dealing with 

 compounds not elements, and with com- 

 bining numbers and not atomic weights. 

 First, one must note his statement of the 

 belief that ' the entire chemical system con- 

 sists of like progressions.' To his mind 

 the elements formed a system correlated 

 and made up of progressions. This is, of 

 course, not the ascending series of de 

 Chancourtois and N"ewlands, but it seems 

 to me a position much nearer to it than 

 was reached by any chemist for more than 

 half a century afterwards. 



Again, in other portions of this volume 

 Riehter speaks of the necessity of deducing 

 quality from quantity and vice versa. Thus 

 he points out that the series of masses men- 

 tioned as forming arithmetical progressions 

 are really series of affinities also, and the 

 relative affinities might be deduced from 

 the relative masses. Much space is given 

 also to the effort at tracing relationships of 

 the specific gravities. While it cannot be 

 positively stated that Eichter foresaw that 

 important part of the periodic law that the 

 properties of the elements are dependent 

 upon the weights, he seems at least to have 

 been possessed with the idea that what he 

 called the masses of the elements had some- 

 thing to do with what he considered the 

 qualities, or that they progressed similarly. 

 And that they in the main progress simi- 

 larly is about all that we know with regard 

 to them at the present day. 



I acknowledge that there is some diffi- 

 culty in sifting out Riehter' s full meaning 

 from the mass of mathematical calculation 

 and one must be careful to avoid reading 

 into his work the thought of later years. 

 It is not strange that the tedium of follow- 

 ing such involved calculations and specu- 



