56S 



NATURE 



[December 29, 192 1 



ber 10 or November 26, the error appears to have 

 been due to his contemporaries, John Robison, Adam 

 Ferguson, and Thomas Thomson. So far as I am 

 aware at present, the only corrections necessary in 

 the Calendar refer to Hooke, who died March 3, 

 1703, according to our present reckoning, and not in 

 1702, and to Spallanzani, February 12, 1799, who 

 held a chair at Pavia, and not Padua. 



Devonport. Edgar C. Smith. 



The Electric Telegraph. 



In the issue of Nature of November 17, p. 381, it 

 is stated that "in 1861 telegraphy, the only practical 

 application of electricity, was in private hands. The 

 earliest telegraph was erected on the London and 

 North-Western Railway between Euston and Chalk 

 Farm so far back as 1837 by Cooke and Wheat- 

 stone. . . •." 



It is strange that no mention is made of the com- 

 pletely equipped reciprocal working electrical telegraph 

 eight miles long (both above and below ground) erected 

 by Francis Ronalds in his garden at Hammersmith 

 in 1816, and fully described by him in a' most in- 

 teresting book published in 1823 ("Description of an 

 Electrical Telegraph and of some other Electrical 

 Apparatus," R. Hunter, 72 St. Paul's Churchyard). 



I thought the story of his treatment by the 

 Admiralty in 18 16, when he asked for inspection of 

 his telegraph with a view to its substitution in place 

 of the semaphores then (and for years afterwards) in 

 use between London and Portsmouth, was well known. 

 He was informed that "telegraphs of any kind are 

 now wholly unnecessary, and none but that in use 

 will be adopted." 



Although Ronalds operated his telegraph by a small 

 frictional hand machine at each end, there can be 

 no doubt — I know he had none — that even with that 

 light charge the eight miles could have been greatly 

 extended, and by larger charges, and, if necessary, 

 repeating stations, it could easily have done what he 

 claimed for it, and he is well known to have been a 

 most cautious, prudent, and accomplished electrician. 

 Had the Admiralty listened to him a solid base would 

 have been laid for the adoption of all the later im- 

 provements which have been made, and electric tele- 

 graphy would have been in use many years sooner. 



The whole of Ronalds's long life showed that his 

 ambition was entirely scientific and not commercial ; 

 he took out no patent for his telegraph, but turned, 

 disappointed, from telegraphy and devoted himself 

 again to other scientific pursuits, in which he attained 

 much success, as is well known to scientific men aoi 

 in England alone. He was elected a fellow of the 

 Royal Society in 1844, and was knighted in 1870, 

 three years before his death, for his "early and re- 

 markable labours in telegraphic investigations." 



Both Cooke and Wheatstone knew of his telegraph, 

 and referred to it in their quarrels. 



Ronalds did not claim to be the inventor of the 

 electric telegraph, the possibility of which had been 

 a matter of discussion for some time by men of 

 science, but rightly claimed to have been the first man 

 to erect and equip an effective working telegraph 

 eight miles long, and capable of indefinite extension. 

 His book shows that he clearly foresaw the future of 

 electric telegraphy. 



J. C. Carter, 

 A Trustee of the Ronalds Librarv. 



65 Sussex Gardens, W.2. 



The reference in our Note was to the first com- 

 mercial telegraph. The history of the invention of the 

 telegraph is well known, but importance must be 



NO. 2722, VOL. 108] 



attached to inventions on the lines on which it 

 developed. A model of the pith-ball telegraph of 

 Francis Ronalds is in the collection of telegraphic 

 apparatus in the Science Museum, South Kensington. 

 It is interesting to remember that jjerhaps the first 

 practical suggestion of an electrostatic telegraph was 

 given in an anonymous letter to the Scots Magazine 

 (vol. 16, p. 73, 1753). It was suggested that as many 

 insulated wires should be used as there are letters in 

 the alphabet. There is good reason for thinking that 

 the letter was written by Charles Morrison, a surgeon 

 and a native of Greenock. 



The W'riter of the Note. 



The Hydrogen-ion Concentration of the Soil in Relation 

 to Animal Distribution. 



The striking relationship between the hydrogen-ion 

 concentration of the soil and plant distribution is 

 apparently not without its parallel in animal distribu- 

 tion. A number of facts concerning the relationship 

 of certain forms of animal life to plant-hosts have been 

 brought together by Fr. Dahl (" Grundlagen einer 

 okologischen Tiergeographie, " Jena, 192 1). He states 

 that a great many animals are exclusively, or almost 

 exclusively, found on certain plants. The association 

 of the silkworm with the mulberry tree is known to 

 all, and it is only with difficulty that it can be brought 

 to feed on anv other leaf than that of the mulberry. 



Since this is so, it follows that animals which in- 

 habit or feed on plants found in regions of alkaline 

 soil must be absent, or almost absent, from those in 

 which the soil is acid. Conversely, the parasites of 

 acid-soil flora must be absent from those large tracts 

 where chalk, limestone, or calcareous silt are found. 



The distribution of worms with regard to the re- 

 action of the soil offers an interesting field of study. 

 The same holds true for the distribution of fresh-water 

 plankton. Soft water, such as that of Dartmoor, is 

 slightlv acid, /)H6-4-68, owing to excess of carbon 

 dioxide in solution, whereas running water, in regions 

 containing appreciable amounts of calcium carbonate 

 in the soil, is close to the bicarbonate equilibrium 

 point, /)H8 3-84. These differences appear to have 

 considerable biological significance, as is easily appre- 

 ciated when one recalls that it has been shown by 

 Prof. B. Moore that the relationship of an amphoteric 

 colloid to its ions depends upon the ratio of the 

 hvdrogen and hvdroxvl ions, namelv, upon the square 

 of the hvdrogen-ion concentration. 



It mav be added that in regard to the influence of 

 the hvdrogen-ion concentration upon plant distribution 

 the additional factors emphasised by Mr. N. M. 

 Comber (Nature, September 2q, p. 146'), and Mr. 

 E. A. Fisher (November 3, p. 306), in criticism of the 

 present writer's letter on the subject (September 15, 

 p. 80), are of undoubted importance and have been 

 discussed elsewhere. They were omitted from the 

 short letter in Nature to make the main idea clearer. 



W. R.. G. .^tkixs. 

 Marine Biological Laboratory, Plymouth, 

 December 13. 



Relativity and Materialism. 



Dr. N. R. Campbell in his interesting letter in 

 Nature of November 24 says that the belief that 

 matter is real is quite unaffected by the principle of 

 relativitv, if the word "real " is used in the common- 

 sense way, which is the onlv way in which the notion 

 of realitv is ever used in physics. He also says that 

 the principle of relativitv may lead us to assert that 

 some things are real which we should otherwise have 

 asserted to be not real. With these assertions I am 

 in cordial agreement. 



