May 14. 1896] 



NA TURE 



phenomena (i) by a consideration of the composition and 

 properties of atmospheric air ; or (2) in consequence of re- 

 marking the results of the analysis of certain pairs or series of 

 chemical compounds, the composition of which illustrates the 

 law of multiples. 



The authors contend for the former view, and adduce the con- 

 tents of the lecture note-book dated 1810 ; but these notes of 

 lecture 17 contain evidence of confusion in the statements 

 made by Dalton himself. In these notes he says (p. 14 

 of the book), "In order to reconcile or rather adapt this 

 chemical theory of the atmosphere to the Newtonian doctrine of 

 repulsive atoms or particulars, I set to \M>rk to combine my 

 atoms upon paper," &c. (P. 15), " In iSoi, I hit upon an 

 hypt>thesis." This hypothesis relates to tlie mutual repulsion of 

 gaseous particles. (!'. 16}, " Upon reconsidering this subject it 

 occurred to me that I had never contemplated the effect of 

 <li(Terence of size. . . . This idea occurred to me in 1805." 

 (P. 17), The different sizes of the particles being once established, 

 "a train of investigation was laid for determining the ««/«&■?■ 

 and weight of all chemical and elementary principles which 

 enter into any sort of combination one with another." 



So that the atomic theory as applied to chemical combination 

 took shape in Dalton's mind according to [his version of the 

 story in 1805. Vet according to another of the note-books, 

 quoted p. 26, he was using symbols to express the atoms of 

 elementary bodies in 1803. The authors notice this conflict of 

 statenienl, but get rid of it by assuming 1805 to be a clerical 

 error for 1803. 



Thomson was probably wrong in attributing the origin of the 

 atomic theory to the study of marsh gas and olefiant gas. But 

 in his exposition of the Daltonian doctrine, prepared only a short 

 time after his interview with Dalton, he illustrates the use of the 

 atomic doctrine by reference to the oxides of nitrogen. This 

 was in his third edition, published 1S07. In his sixth edition he 

 introduces the oxides of carbon as well as the oxides of nitrogen. 

 Thomson, therefore, from the time of his interview with Dalton 

 retained the impression that the genesis of the theory was 

 intimately connected with the facts known to Dalton as to 

 chemical combination in multiple proportions, though he was 

 evidently not clear as to the particular case first considered. 

 That it was the oxides of nitrogen which first attracted Dalton's 

 attention is, however, probable from the fact that he refers to 

 them in the following noteworthy passage which occurs in his 

 paper on the atmosphere read at Manchester, November 12, 

 1802 : " These facts clearly point out the theory of the process : 

 the elements of oxygen may combine with a certain portion of 

 nitrous gas, or with twice that porlion, but with no intermediate 

 quantity." The authors have succeeded in discrediting the story 

 about marsh gas, but it still reinains doubtful whether Dalton's 

 recollections in iSio of what occurred six or seven years before 

 are more trustworthy than the impressions of Thomson received 

 much earlier, when it is a question as to the order in svhich 

 various considerations came before his mind in the long course 

 of meditation which led to the adoption of his theory. 



VoUR Rkviicwicr. 



An Advance in Riintgen Photography. 



Since my last communication I have been pursuing the study 

 of the photography of the soft tissues in the living adult subject, 

 and making attempts to see shadows of them on the fluorescent 

 screen. In a previous communication I was able to state that I 

 had accomplished these in the region of the neck, the tongue, 

 hyoid bone, larynx, &c. Proceeding downwards, I have now 

 photographed and seen shadows of the cardiac area. In the 

 ])hotograph the diaphragm is clearly indicated below ; the pyri- 

 forni shape of the cardiac area is well made out, the base down- 

 wards, apex upwards, and the right and left borders show the 

 relationship to the spine and ribs. Juil.N M.vcintyrI!. 



179 Bath Street, Glasgow, May 9. 



PROJECTS FOR ANTARCTIC KXPLORATION. 



OX January 28, 1 841, Captain James Clark Ross and 

 his comrades on her Majesty s ships Erebus and 

 Terror, saw for the first time the j^iant volcanoes, rising 

 in latitude 78"' 30' S., which bear the names of the only 

 vessels that ever sighted them. 



Fifty-five years later we remain in possession of no 



NO. 1385, VOL. 54] 



more information regarding these regions than was 

 brought home by the discoverer. This is a circumstance 

 absolutely unique in the modern history of geography. 

 During these fifty-five years the map of Africa has 

 developed from a carle blanche into a well-ordered de- 

 lineation of mountains, lakes and rivers, even towns and 

 villages the names of which are household words. In 

 the far North the limits of the unknown have been 

 and are still being strenuously pushed back. It is 

 only in the far .South that the explorer's march has been 

 stayed, and during the last ten or fifteen years the 

 importance of securing a farther advance in this direction 

 has been given expression to, with increasing frequency 

 and emphasis, by the scientific men of all countries. 

 The latest and most weighty statement on the subject 

 was the resolution of the .Sixth International Geographical 

 Congress, drafted in London by the leading geographers 

 of Europe, to this effect : 



"That the Congress record its opinion that the explora- 

 tion of the Antarctic regions is the greatest piece of 

 geographical exploration still to be undertaken. That, in 

 view of the additions to knowledge in almost every branch 

 of science which would result from such a scientific e.x- 

 ploration, the Congress recommends that the scientific 

 societies tliroughout the world should urge, in whatever 

 way seems to them most eftective, that this work should 

 be undertaken before the close of the century." 



It is clear to all scientific men that, although the 

 recent experimental trips of Scottish and Norwegiaii 

 whalers to the Antarctic regions have led to some 

 distinct advances in our knowledge, and have rightly 

 occupied a good deal of attention, they leave the question 

 of serious exploration untouched. In the absence of a 

 real expedition, we must continue to eagerly utilise 

 every scrap of information which may be obtained by 

 any means ; but such trifles are only of provisioiial 

 value. The drowning man may, for want of other floats, 

 catch at straws, but the least critical spectator of this 

 proverbial tendency would not argue that a life-belt w-as 

 therefore unnecessary. 



Antarctic exploration, if newspaper reports are to be 

 trusted, has been commenced by the American Dr. Cook, 

 who accompanied Lieutenant Peary on one of his 

 journeys in Greenland, and has now got together a small 

 scientific party on board two little sailing vessels of only 

 100 tons, with which he hopes to penetrate to the coast 

 of Graham's Land and winter there. Weddell, in 1823, 

 succeeded in reaching 74" 15' S., in that neighbourhood, 

 one of his vessels being only 65 tons, so that small 

 size does not necessarily mean failure. If Dr. Cook 

 has experienced ice-navigators with him, he will probably 

 be able to effect a landing and collect some useful 

 information. His equipment, however, is, we fear, inade- 

 quate to the task he has undertaken, and much must not 

 be expected from it. 



A more serious effort is announced as almost ready. 

 It is to be commenced in September this year, under a 

 flag which we believe has not hitherto appeared in polar 

 regions, that of Belgium. The proposed expedition is 

 being arranged by Lieut. A. dc Gerlache, of the Berlin 

 Navy, under the auspices of the Royal Belgian (ieo- 

 graphical Society, and the expenses, which are estimated 

 at ^10,000, are to be met by public subscription. It is 

 said that a large proportion of the money has been 

 promised, the Brussels municipality have voted a grant ; 

 but until the whole of the cost is guaranteed, it would 

 be rash to look upon this or any other expedition as 

 a settled aflair. \ strong scientific staff is intended to 

 accompany the vessel, which will probably try to get 

 south along the east coast of Graham's Land. 



In Germany the enthusiasm for Antarctic exploration 

 has been gradually rising, and a strong Committee was 

 appointed at the Eleventh German Geographical Con- 

 gress, held last year at Bremen, to organise an expedition. 



