March 26, 1896] 



NATURE 



487 



the path as from /3 - o Canis Minoris eastwards passing i70° + o° 

 and disappearing behind a cloud about 5° beyond the latter 

 point. The duration was 6^ seconds. 



Comparing the two observations, I find the radiant was in 

 Pisces at 18° + 5°, which at the time of the meteor's appearance 

 had an altitude of about 4° only in due west. The meteor was 

 first seen from Sunderland when it was over a point near York at 

 a height of 59 miles, and when last seen from York it was over 

 Heligoland at a height of 49 miles. The Sunderland observer 

 noticed the meteor a little earlier in its flight than the observer 

 at York ; while at the latter place it was retained much longer 

 in view than at Sunderland, where a cloud appears to have ob- 

 scured the terminal stages of the phenomenon. The whole 

 length of its path was alx)ut 370 miles ; Mr. Backhouse, at Sunder- 

 land, watched the meteor traverse 195 miles, so that his estimate 

 of the duration would give 30 miles per second for the velocity. 

 Mr. Clark saw 338 miles of the path, and his estimate of 32 

 seconds would give loj miles per second. The difference may 

 be partly accounted for on the supposition that owing to the re- 

 sistance of the atmosphere the meteor slackened considerably in 

 speed during the latter part of the flight. 



When last seen by Mr. Clark, the meteor was close to its 

 anti-radiant and travelling in a nearly direct line away from the 

 observer, so that its apparent motion would be very very slow, 

 and the object must have looked like a hazy almost motionless 

 star near the eastern horizon. 



The radiant point at 18° + 5° in Pisces indicates a place in the 

 heavens where no meteor shower has ever been observed in the 

 first quarter of the year — in fact, on March i it is only 35'' east 

 of the sun. In the summer and autumn, when the constellation 

 Pisces is favourably presented in the dark sky, many meteor 

 showers radiate from it and some brilliant fireballs have been 

 directed from a similar position. The following instances may 

 be noted : — 



The mean position seems to be about 13° + 5°. It declines so 

 far to the west in November that n3 showers have been 

 seen from it afterwards, though it occasionally yields fine 

 slow-moving fireballs. Thus in 1891 Dec. 20, 8h. 38m., I saw a 

 meteor, equal to Venus, moving very slowly from 124°-}- 64° to 

 l59° + 49^> a"d presumably from this radiant in Pisces. 



Bristol, March 19. W. F. Denning. 



Barisal Guns. 



In regard to the " barisal guns" or " mist pouff"ers," lately 

 described in Nature, similar sounds have been heard in this 

 region. 



On July 4, 1808, the expedition of Captains Lewis and Clark 

 was at this place. Under that date we find the following entry 

 in their journal : " Since our arrival at the P'alls we have 

 repeatedly heard a strange noise coming from the mountains in 

 a direction a little to the north of west. It is heard at different 

 periods of the day and night, sometimes when the air is perfectly 

 still and without a cloud, and consists of one stroke only, or five 

 or six discharges in quick succession. It is loud, and resembles 

 precisely the sound of a six pound piece of ordnance at the dis- 

 tance of three miles. The Minnatarees frequently mentioned 

 this noise like thunder, which they said the mountains made, 

 Tjut we paid no attention to it, believing it to be some super- 

 stition or falsehood perhaps. The watermen also of the party 

 say that the Pawnees and Recaras give the same account of a 

 noise heard in the Black Mountains [Black Hills] to the west of 

 them." 



The mountains towards which these noises were heard were 

 the main range of the Rockies, and distant about eighty miles. 

 In 1854, Mr. Doty, of Governor Stevens's party, heard similar 



NO. 1378, VOL. 53] 



noises. He was near enough to the mountains to be certain that 

 the noises came from them The locality where Mr. Doty heard 

 them was where the direction observed by Lewis and Clark 

 would strike the mountains. 



Plenty of white men have been in this country for the last 

 thirty years, or since 1866. I have made careful inquiry among 

 pioneers, but cannot learn that the noises have been heard since 

 Mr. Doty's report. 



In 1 8 10 a party, outfitted by John Jacob Astor, made an over- 

 land trip from the Missouri to the mouth of the Columbia. 

 They tried to go through the Black Hills, but were obliged to 

 withdraw and flank them. In these hills they note as follows : 

 " In the most calm and serene weather, and at all times of the 

 day or night, successive reports are now and then heard among 

 these mountains, resembling the discharge of several pieces 

 of artillery. Similar reports were heard by Messrs. Lewis and 

 Clark in the Rocky Mountains. 



Such explosions are also said to occur frequently in Brazil. 

 " Vasconcellis, a Jesuit father, describes one which he heard in 

 the Sierra, or mountain region of Peratininga, and which he 

 compares to a park of artillery." Chas. H. Robinson. 



Great Falls, Montana, March 5. 



Ostwald's Energetics. 



It may not perhaps be irrelevant to point out that even were 

 it permissible to assert — as Prof. Fitzgerald conclusively shows 

 that it is not — that because certain natural processes do not 

 under actual conditions reverse, therefore they are irreversible, 

 the examples of irreversibility in nature, on which Prof. Ostwald 

 founds his "fourth attack" on the mechanical theory, are 

 singularly ill-chosen. He directs us to the life-histories of 

 organisms, these life-histories themselves being but a very brief 

 portion of the indefinitely long series of transformations which 

 the matter for that short time identified with them is going 

 through. Yet even within this narrow range reversible actions 

 are to be found. Surely all metabolic processes must be regarded 

 as such. Moreover at this very moment there may quite pos- 

 sibly be built into our own bodily tissues, matter which some 

 generations ago entered into the physical composition of our 

 ancestors, has since been degraded from the rank of organic 

 substances altogether, and is now through new-old combinations 

 and re-combinations once more raised to its former position and 

 forms part of a living organism. If this can come to pass, vital 

 phenomena are clearly not irreversible. It may take much more 

 than the lifetime of a man or of a tree for the whole cycle of 

 operations to be complete ; but when it is complete, we have 

 as fair an example of a reversible series as we are likely to find 

 in nature. E. M. C. 



"E. M. C." calls attention to the fact that if trees do not grow 

 into seeds they do grow seeds. This and other cases of repro- 

 duction are no doubt cases of reproducing the original condition, 

 but Prof. Ostwald would rightly refuse to recognise them as 

 cases of reversion to the original condition in the dynamical 

 sense. In the case of a dynamical reversal the flow of energy 

 is reversed. In order to have a case the reverse of the growth 

 of a tree, it would be necessary to have a tree which radiated 

 heat back to the sun in the reverse direction to the flow which at 

 present takes place from the sun to the tree. Otherwise Prof. 

 Ostwald would rightly deny that it was a genuine case of dy- 

 namical reversion. It was on account of this complication in- 

 volved in Prof. Ostwald's example that I cited the very much 

 more simple cases of irreversible thermodynamic operations, such 

 as friction and flow of heat from hot to cold. To cite the very 

 complex organic cases of irreversible operations instead of the 

 simple ones, is only to cloud the question with complexity. 



Prof. Boltzmann has already devoted himself to combat Prof. 

 Ostwald's Energetics, and it would be well for those who feel any 

 leaning towards the latter to study the views of this father of 

 the kinetic theory of gases. Geo. Eras. Fitzgerald. 



Trinity College, Dublin, March 18. 



Classifying Crushed Ore by Trommels. 



It was very pleasing to me to read in your valuable publica- 

 tion of November 7, 1895, the favourable criticism written by 

 your correspondent, Mr. T. K. Rose, on my report on the loss 

 of gold in the reduction of auriferous veinstone in Victoria. 

 Nevertheless, permit me to make a few remarks to endeavour to 



