534 



NATURE 



[Ai'Kii, 6, 1899 



instance, ihe view taken in Herr Dedekind's book. "Was sind 

 und was sollen die Zahlen." As regards the opening sentences 

 of Chapter xv., the authors have apparently misunderstood the 

 point of my objection. With the usually received definition of 

 convergence of an infinite product, n(l - a„), if convergent, is 

 different from zero. So far as the passage quoted goes, 

 n(i — a„) might be zero ; and it is therefore not shown to be 

 convergent, if the usual definition of convergence be assumed. 

 As to the passage quoted from p. 232, I must express to the 

 authors my regret for having overlooked the fact that the par- 

 ticular rearrangement, there made use of, has been fully justified 

 in Chapter viii. Whether Log .v is or is not, at the beginning 

 of Chapter iv. , defined by means of a string and a cone, will be 

 obvious to any one who will read the whole passage (p. 46, 

 line 16, to p. 47, line 9) leading up to the definition. 



W. BURNSIDE. 



The Tetravalency of Oxygen. 



The discovery of the new and easy method of preparing the 

 pure oxygen phosphide 0\\ (or Le Verrier's phosphorus sub- 

 oxide) by the acidification of the solution of phosphorus in 

 " alcoholic potash," should draw attention to the remarkable 

 fact that the oxygen atom can be therein symmetrically repre- 

 sented only as tetravalent and not divalent, and that it is 

 probably an inorganic, non-carbon, closed-ring molecule : — 



I. 2. 

 P P P P 



11X11°' l><h'li;/-v 

 p- — -p p p p p 



Without discussing the valency or " validity," as I have 

 termed it, of phosphorus, my point is that oxygen is here 

 tetravalent. The silver analogue (?) OAg^, or 



Ag Ag 



Ag Ag 



is known. And doubtless others. There ought, therefore, to 

 be no further hesitation in definitely accepting the oxygen atom 

 in the CO molecule as tetravalent, and in proceeding with 

 investigations which shall elucidate, in terms of physical chem- 

 istry, the remarkable fact of the "alternating valency" of the 

 non-metallic atoms. Oxygen has as clearly two valence values 

 as phosphorus and nitrogen. 



The change in the valency of oxygen seems to be connected 

 with "polymerisation." In 1888 I wrote in the Philosophical 

 Magazine, vol. xxv. p. 232 : — 



"The stimulus — if I may so term it — to polymerisation in 

 these cases seems to be due to the development, in ways that 

 current research are seeking to explain, of the higher valency, 

 or, as it may be preferably termed, the validity of oxygen, or 

 the ter\'alidity, for instance, of chlorine in "hydrochloric acid 

 solution " used as "a polymeriser," H — CI = =. It is .signi- 

 ficant that there are few cases of polymerisation where oxygen 

 is not concerned. . . . Probably more ring formuhe in /'//organic 

 bodies will come to light, and they will aflect the maypole 

 hypothesis — as it may be called — of the domination of the 

 central polad atom." 



This prediction has, I believe, since been verified, and the 

 benzene-ring style of Kekul^ is no longer viewed as exclusively 

 characteristic of carbon. The remarkable volatile osmium 

 compound is probably 



HO OH 



I ^'Os/ I 



HO OH 



where oxygen is tetravalent as it is in Kriedel's (HjOjOCIII. 



I would, therefore, venture to suggest that possibly my two 

 papers in the Phil. Mag. may still be worth Iialf an hour's 

 attention from gentlemen who would find some curious com- 

 pounds therein discu.ssed— compounds whose physical chemistry 

 may perhaps now be found worth examination in the light of 

 the newer methods, and also in the light of the developing 

 investigations concerning the ether and the intramolecular 

 equipoise of the atoms constituting the chemical molecule. 



Banbury, March 25. J. F. Hkyes. 



NO. 1536, VOL. 59] 



THE PROGRESS OF WIRELESS TELEGRAPHY. 



WE recently referred to the first messages transmitted 

 over the English Channel between the .South 

 Foreland and Boulogne by Marconi's system of wireless 

 telegraphy. During last week the English station was 

 visited by I'rof. Fleming, who has written his experiences 

 to the Times. 



An idea of the present state of the problem can be con- 

 veniently gathered from this communication. First as to 

 the certainty of the results obtained, I'rof. Fleming states : 



"Throughout the period of my \isil messages, signals, 

 congratulations, and jokes were freely exchanged between 

 the oper.itors sitting on either side of the Channel and 

 automatically printed down in telegraphic code signals 

 on the ordinary paper slip at the rate of twelve to 

 eighteen words a minute. Not once was there the 

 slightest difficulty or delay in obtaining an instant reply 

 to a signal sent. No familiarity with the subject re- 

 moves the feeling of vague wonder with which one sees a 

 telegraphic instrument merely connected with a length 

 of 150 feet of copper wire run up the side of a flagstafT 

 begin to draw its message out of space, and print down 

 in dot and dash on the paper tape the intelligence ferried 

 across thirty miles of water by the mysterious ether.' 



Signor .Marconi by much work has arrived at great 

 simplicity. 



"With the exception of the flagstafT and 150 feet of 

 vertical w ire at each end, he can place on a small kitchen 

 table the appliances, costing not more than 100/. in all, 

 for communicating across thirty or even one hundred 

 miles of channel. . . . The distance to which effective 

 signalling extends varies as the square of the height of 

 the rod. .-V wire 20 feet high carries the effective signal 

 one mile, 40 feet high four miles, 80 feet si.xteen miles, 

 and so on.' 



We are very glad to print the following extract from 

 Prof. Fleming's letter : 



" The general public are not much concerned with 

 questions of i)rionty or with the claims or suggestions of 

 rival e.xpcriiiientalists, but they are interested in ascer- 

 taining the serious possibilities of that which has been 

 actually achieved. Signor Marconi has never hesitated 

 to acknowledge that he has built upon the foundations 

 laid by others, but a vast gulf separates laboratory ex- 

 periments, however ingenious, from practical large scale 

 demonstrations conducted with all that regularity and 

 freedom from failure which is the absolute condition of 

 their public utility. 



" I cannot help thinking that the time has arrived for a 

 little more generous appreciation by his scientific con- 

 temporaries of the fact that Signor Marconi has by 

 minute attention to detail, and by the important addition 

 of the long \ertical air wire, translated one method of 

 space telegraphy out of the region of uncertain delicate 

 laboratory experiments and placed it on the same footing 

 as regards certainty of action and ease of manipulation, 

 so far as present results show, as any of the other methods 

 of electric communication employing a continuous wire 

 between the two places. This is no small achievement." 



There can be no doubt that what this system will do in 

 the future for those who live on coastlines or go down 

 to the sea in ships is destined to be of great importance. 

 Already the usefulness of light-ships is increased ten- 

 fold. The tlect mancvuvres of the future may be flagless. 

 Sea routes by means of an international concert pitch 

 may be turned into exchanges — but theie is no end of 

 the possibilities thus opened out by this new develop- 

 ment of the results of the study of the " useless." 



Prof, Fleming, in the course of his long and interesting 

 letter, points out the importance of some new Hoard of 

 Trade regulations "for the use of the ether"— the term is 

 distinctly goml— lest vagiant electric wa\es should inter- 

 fere with the official ones. Even the ether, then, may 

 yet be dismissed with costs. 



