January 30, 1896] 



NATURE 



295 



LETTERS TO THE EDITOR. 



[2'Ae Editor does not hold himself responsible Jor opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.'] 



Prints of Scars. 



The accompanying print is sent with a two-fold object. First, 

 for its intrinsic interest in showing how thoroughly and definitely 

 a grafted slice of skin and flesh has established itself under its new 

 conditions, retaining its original characteristics unchanged during 

 thirty years. Secondly, because of its probable interest to surgeons 

 in illustrating the ease and completeness with which a record 

 can be kept of the process and results of the cicatrisation of 

 wounds. 



Prints are more clear, more cheap, and more trustworthy than 

 photographs. They are not distorted through perspective, nor 

 blurred owing to differences of focus ; they can be taken in any 

 light, and their scale is absolutely correct. They are made by 

 rolling the scarred part on a porcelain pallet or metal slab, that 

 has been covered evenly and very thinly with printer's ink ; or, 

 conversely, the pallet and paper are rolled upon the scar. As 

 many duplicate prints can be taken as desired. I have written 

 at so much length about these and alternative methods of printing 

 in my book, " Finger Prints," and elsewhere, that I need say no 

 more about them now. The print sent herewith is a photographic 



Enlarged print of a misplaced graft of flesh on the side of a thumb, 

 thirty years after it was made. 



enlargement, being more suitable for rough process-printing than 

 the somewhat minute originals ; but one of these is also enclosed. 

 The history of the graft is as follows: J. R. H., who is a 

 solicitor in large practice, when he was twenty-five years old, 

 sliced a piece clean off the thumb of his left hand. He was 

 cutting cardboard with a sharp knife guided by a rule, upon 

 which the thumb pressed, and which it slightly overlapped. The 

 piece that was cut off fell on the table ; it was at once picked 

 up, clapped upon the wound, and the thumb was tightly 

 bandaged. After a few days reunion had taken place, and the 

 wound was healed. It then proved that the graft had not been 

 replaced in its original position, but crossways to it, as seen by 

 the papillary ridges in the accompanying print, taken in 1895, 

 thirty years after the accident. ^'~ '" ~" 



Francis Galton. 



The Cause of an Ice Age. 

 Sir Robert S. Bai.i. appears to admit the correctness of 

 Mr. Culverwell's argument against Croll's astronomical theory 

 of an Ice Age so far as, that " the direct sun-heat received on any 

 parallel at the time of greatest eccentricity is the same as that 

 now received on the parallel not more than three or four degrees 

 north " ; and then proceeds to explain, with perfect truth, that 

 " the actual temperature in a region depends, not merely upon 



the sun-heat there received, but also upon the transference of 

 heat across the boundaries of that region." 



Now the causes upon which the transference of heat depend, 

 viz., the prevailing winds and the ocean currents, rest ultimately 

 upon the sun-heat received over the whole globe. The sound- 

 ness of Mr. Culverwell's argument therefore seems to hinge 

 upon whether the general shift of the isotherms of sun-heat 

 three or four degrees southward would be incapable of greatly 

 altering the winds and currents. If this were so, it might be 

 admissible to reason upon the sum total of the local climatal 

 effects at a period of great eccentricity, with the winter in 

 aphelion, from the conditions of temperature as they now exist. 

 If a shift three or four degrees southward would not appreciably 

 alter these currents, I think Mr. Culverwell's argument against 

 Croll's theory a strong one ; and to reply effectually to it, it 

 ought to be explained that such a slight shifting of the isotherms 

 of sun-heat would be likely to affect those currents to so great 

 an extent that the then conditions of local temperature would 

 not bear comparison with the present — as, for instance, of 

 Cornwall then with Yorkshire now. O. Fisher. 



Harlton, Cambridge, January 17. 



Barisal Guns and Similar Sounds. 



In Colonel Godwin-Austen's interesting letter on the 

 Barisal guns (page 247 ante), he mentions as suggested sources of 

 these remarkable sounds fireworks {i.e. , bombs, cannon), bursting 

 bamboos in jungle-fires, thunder-claps, landslips, the falling of 

 river-banks or sand-banks, and seismic disturbances ; but he 

 does not add what seems to me to be a more probable source of 

 the sounds, namely, ball or globular lightning, known to the 

 French as klairs en boule. 



It is true, as I stated in my letter to the Times in August 

 last, that Faraday, so late as 1838, said : — "That phenomena 

 of balls of fire may appear in the atmosphere I do not deny, but 

 that they have anything to do with the discharge of ordinary 

 electricity, or are at all related to lightning or atmospheric 

 electricity, is much more than doubtful." (" Researches," sec, 

 1641.) 



Snow Harris, however, in his book on "Thunderstorms," 1843, 

 recognises the phenomenon as a case of glow discharge, often 

 terminating in disruptive discharge, as in the case of H.M.S- 

 Montague. After this, the reported cases of ball-lightning and 

 the damage caused by their violent explosion are numerous, and 

 some remarkable ones have been described lately in Nature. 

 When of lower tension, these fire-balls, as they were called by 

 the older physicists, may envelop the person without doing any 

 harm, a striking example of which is given in Shakespeare's 

 fulius Civsar, Act i. Scene iii. 



The explosive sounds heard by the Rev. W. S, Smith, while 

 skating on Lough Neagh, may still be due to globular lightning. 

 The dry atmosphere occasioned by frost is highly favourable to 

 the development of atmospheric electricity ; and we have still to 

 learn whether these electrical globes will not account for the 

 observed phenomena. C. Tomlinson, 



Highgate, N. , January 20, 



In connection with the correspondence on mysterious atmo- 

 spheric sounds, which originated with Prof. Darwin's communi- 

 cation in the issue of Nature for October 31 last, I have 

 official sanction for forwarding the following extracts from the 

 meteorological logs of vessels visiting high latitudes. 



S.s. /Resolute, Captain W. Deuchars ; 8 p.m., July 30, 1883^ 

 in 71° 9' N., I2°28'W. — "Six reports like those of guns heard to 

 the westward, supposed to be caused by electricity, as no ships 

 are thought to be in the vicinity." Wind during the day calm 

 to very light easterly airs ; weather foggy ; sea smooth, with a 

 very slight south-easterly swell ; pressure and temperature as 

 follows : 



Air temperature. 

 Dry bulb. Damp bulb. 



Sea tempera- 

 ture. 



50-0 

 42-0 

 40-8 

 46-5 



48-8 

 41-8 

 40-5 

 46-5 



41-5 

 37-0 

 37 -o 

 35 -o 



S.s. Windward, Captain A. Murray; 4a.m. June 12, 1883, 

 in 71° N., 7i" W. — " There is a distinct murmur as of a water- 

 fall from the island " [of Jan Mayen]. Calm ; weather foggy ; 



NO. 1370, VOL. 53] 



