NATURE 



\ytme 6, 1872 



the fact that in 1770— 1773, Lagrange published an elaborate 

 memoir at Turin under the tide "Memoire sur I'utilite de la 

 Methode de prendre le Milieu entre le; resultats de plusicurs 

 Observations," &c. /'/,/(■ "Oluvres de Ligrange," edited by 

 J. A. Serret, vol. 2. 



I have never seen any notice of this memoir except a transla- 

 tion of a part of it into German by Encke, published in the 

 Berliih-r Jalirbiii-h for 1853. Thus in the abstract of a memoir 

 by Mr. J. W. L. Glaisher, given in the notices of the Royal 

 Astronomical Society for April 1872, the name of Lagrange does 

 not occur. 



I think that the English mathematician, Thomas Simpson, 

 busied himself with this problem about 1750, but I am not able 

 to refer to his works. AsAfll Hali. 



Washington, May 22 



The Volcanoes of Central France 



An unlucky error, perhaps mine, in the letter on the 

 "Volcanoes of Central France," p. So, will quite prevent any 

 reader finding the paper I mentioned ff May 1S65, which, in- 

 stead of being in the GcntUmait's Magazine, was in the English- 

 man's magazine, a short-lived periodical, begun and ended, I 

 think, with that year. Asyourtwocorrespondents, Prof. Corfield 

 and the Rev. Mr. Webb, like the writer of that paper, repeat 

 the late Dr. Daubeny's most marvellous "conclusion" that there 

 might have been nothing more eruptive in the phenomena th.-m 

 " bursting out of flames" from earthquake fissures, a.id even that 

 the fires mentioned by Sidoniusand Avitus might be " domestic 

 conflagrations," may I briefly indicate the grounds that make these 

 suppositions to me incredible ? These fires, as named in the 

 portions of each document that I have translated — quite distinct 

 from the conflagration of some public building on the Easter 

 festival of a previous year, which both writers afterwards relate 

 at greater length as an earlier and less known case of successful 

 prayer by Mamertus, the memory of which had encouraged him 

 under these "prodigies" and "portents," the ignes (not in- 

 ccndia) that both writers make a chief or the chief part of the 

 "terrors" — (Sir'onius, indeed, names the earthquakes before 

 them, but Avitus twice over puts the fires first) — these were 

 crehri and assidni, continual for two or three years, yet not a word 

 of what they fed on or wdut valuables they destroyed, and they 

 were only scrpcjiammali. Their being so sometimes is plainly 

 named by .Sidonius as an unusual and greater portent. Now, I 

 never heard of any "domestic" fires that were not "Jlamiiiaii," 

 whereas volcanic eruptions, even severe, seldom if ever involve 

 flame truly so called, though their strongly illuminated smoke 

 may often by night be mistaken for flames, and has led them to 

 be called in extreme cases, as Sidonius here said, sa-pe flammali. 

 He adds that when thus "Jiaminali" tliey did, or rather 

 threatened to do, the only mischief named as even apprehended 

 from them at the capital, the endangering frail roofs by a load of 

 ashes thrown over, supcrjccto favillarnm nwiite. Now, surely 

 this is not an effect of any cedile conflagrations however often 

 repeated (a repetition that would anywhere have been regarded 

 rather as .suspicious of incendiaris.m than as "prodigious" and 

 preternatural). Nor would any such accidents lead Avitusto a.sk 

 in his sermon to those who remembered all, "Who would 

 not dread the Sodomitic showers ? " Again, Mr. Webb con- 

 ceives that earthquakes might not only drive the wealthier pirt 

 of the population out of the city, "but, as it would seem, the 

 beasts into it !" I never heard of shocks producing so singular 

 an effect as driving any living thing into cities or buildings, and 

 cannot conceive .vhat natural event could so drive them, unle5S 

 what is here by both vv-itnesses implied, "Sodomitic sho'.vcrs" 

 of hot or cumhenng JavilliT. Such showers, which we know to 

 be often carried, from eruptions involving no lava, scores or even 

 hundreds of niiles, in the direction of the prevailing winds, would 

 be carried from any of the well-known cones of the Forez or 

 Vivarais, towards, or even far beyond, Vienne ; and wild animals, 

 fleeing north-eastward, would have no refuge but under roofs ; 

 and if private house doors were habitually shut (as now in 

 England) might crowd into the colonnades [fori laUra) of that 

 capital city. This incursion of the wild deer, bears, and wolves 

 into towns was so well remembered as to become, in the later 

 chroniclers, Gregory of Tours, &c., dwelt upon among the main 

 "prodiges" of the time, along with the earthquakes and burn- 

 ings of buildings, though any other fires cease to be implied ; 

 and the reason of this is obvious on comparing their accounts. 



They all copy one another, and the earliest, whose sole authori- 

 ties were those two pompous and involved writers, mis-read them 

 exactly as our moderns (except Sir F. Palgrave) appear to have 

 done, confusing together the fires of the "prodigies," that led 

 to the Rogation fasts with the earlier a^dile conflagration at some 

 Easter, said to have been prayed out by Mameitus, which occu- 

 pies both the writer and preacher immediately after, and at 

 greater length than these well-known " terrors " remembered by 

 those they addressed personally. 



The whole strikingly shows, as Sir F. Palgrave said, the 

 fallacy of geological inferences from the " silence of history " (or 

 what may be deemed silence) in limes and places practically pre- 

 historic, or at least preter-historic. He showed that, but for 

 Pliny and a mere accident, we should probably have been as 

 ignorant of even the Pompeii and Hcrculaneum eruption as of 

 these equally attested ones. Again, the Spaniards would have 

 preserved us no memory of the rise of JoruUo, in the very last 

 century ; and )et probably no part of Gaul in the generation when 

 the Romans lost it was really more settled and populous than 

 Mexico in its third century of .Spanish rule. The only important 

 colonies within moderate shower-range of the eastern volcanoes 

 were Vienne and Lyons, the latter farther off, and not at that 

 time a capital, indeed but little heard of in those early middle ages. 

 And fires, not called damaging, only " prodigious " and terrifying 

 to Vienne, and causing "Sodomitic showers" there, need not 

 have been within a few miles, but far in the wilds, then hardly 

 trodden, of its mountainous south-western horizon. 



E. L. Garbett 



7, Mornington Road, N.W., June i 



Temperature of the Deep Sea 



Will you allow me to ask, through your pages, if there be 

 any rule for ascertaining the temperature of the sea at given 

 depths below the surface ? To practical electricians such a rule 

 would be very valuable. 



I will state a case. There is a submarine cable connecting 

 two stations, A and B, 150 miles distant. The temperature at 

 A is 75° Fah. ; that at B, 68° Fah. ; and the average depth 

 at wliich the cable lies 120 fathoms : what is the average tem- 

 perature of the cable ? 



If you could refer me to any work in which this point is treated 

 I shall be obliged. F. 



ENDOWMENT OF PROFESSORSHIPS 



THE following correspondence between Professors H. 

 E. Roscoe and B. Stewart, of Owens College, Man- 

 chester, and the Chancellor of the Exchequer, is published 

 in the Times of Monday last : — 



"To THE Right Hon. Robert Lowe, Chancellor 

 OF THE Exchequer. 

 "Owens College, Manchester, May 21, 1S62. 



" Sir, — In the Times of May 17 you are reported, at the 

 presentation for Degrees at the University of London, to 

 have pointed out ' how the endowment of Professorships 

 naturally tended to make teaching inefficient (seeing that 

 the revenues come in independently of the results of teach- 

 ing), suggesting that those who had any money to spare for 

 the advancement of education should rather make it avail- 

 able in the forms of Scholarships and Exhibitions.' 



" While we gratefully acknowledge the many services 

 which, as Chancellor of the Exchequer, you have rendered 

 to tlie cause of knowledge, we yet feel most strongly that 

 the above expressions are calculated to mislead, and that 

 were your suggestions to be carried out, the result would 

 be fatal to the higher education of this country. 



" \Vc therefore request permission to lay before you our 

 own views on this most important subject. Writing from 

 the very house once inhabited by Cobden, we feel proud 

 to be connected with a city which was the birth-place of 

 Free Trade ; yet we feel equally privileged to form part 

 of a very useful institution which never could have existed 



