April 2 1, 1887] 



NA TURE 



581 



which has previously come before my notice in eases where other 

 minds have looked at this sameqviestion — I venture to think you 

 will allow me a few lines to show from what it arises, in the hope 

 of expounding a subject which, popularly understood, must 

 undoubtedly appear a little complex. 



If, instead of taking the "concrete equivalent " of the defini- 

 tion, which the Professor has taken, though it is only used in the 

 original " for our present purpose," we take " the broadest and 

 most complete definition of life," . . . "the continuous adjust- 

 ment of internal relations to external relations" ("Principles of 

 Biology," vol. i. p. 80), we shall find that the changes under- 

 gone by minerals, even the physiological changes, will not 

 obviously come within it ; for it appears to me that, in the 

 illustrations named in last week's Nature, the minerals only 

 display a continuous adjustment of internal changes to external 

 changes. A change in the incident forces produces a change in 

 the internal molecular arrangement of the mineral ; a further 

 change in the forces k followed hy a further molecular, or molar, 

 rearrangement in the mineral, and so on. There is no antici- 

 patory, or induced, change — this is the point — in the mineral, 

 which will correspond with the change which usually is connected 

 with, and is sequent upon, the first environmental change, as is 

 the case with living organisms. A quotation from the " Prin- 

 ciples of Biology " (vol. i. p. 79) in conclusion will, I hope, now 

 make my me.aning clear. " If a creature's rate of assimilation 

 is increased in consequence of a decrease of temperature in the 

 environment ; it is that the relation between the food consumed 

 and heat produced, is so re-adjusted by multiplying both its 

 members, that the altered relation in the surrounding medium 

 between the quantity of heat absorbed from, and radiated to, 

 bodies of a given temperature, is counterbalanced. If a sound 

 or a scent wafted to it on the breeze, prompts the stag to dart 

 away from the deer-stalker ; it is that there exists in its neigh- 

 bourhood a relation between a certain sensible property and 

 certain actions dangerous to the stag, while in its organism there 

 exists an adapted relation between the impression this sensible 

 property produces, and the actions by which dangei is escaped." 

 The importance attaching to the word relation in this quotation 

 has led me to emphasise it by italics. 



Churchfield, Edgbaston F. Howard Collins 



Oldhamia 



Prof. .Sollas's ingenious suggestion as to the origin of 

 Oldhamia (NATURE, p. 515 ; Proc. R.D.S. p. 355) undoubtedly 

 deserves very careful consideration ; but it appears to me to leave 

 some serious difficulties unexplained. For instance, the follow- 

 ing occur to me after reading his paper and after examining two 

 very fine specimens — one of 0. anliqua, the other of 0. 

 raUiata — recently placed in my hands by Mr. R. W. Scott, 

 F.R.S. : — (l) The "puckerings," which are supposed to simu- 

 late the organism, are more definite in their boundaries than is 

 usually the case with the ridgy or wavy "rucking up" which 

 often occurs in phyllites as a first stage in the production of 

 Ausweichungsclifage. (2) While I can trace down into the mass 

 of the slate a certain puckering, I am at present unable to 

 connect it with the Oldhamia visible on the upper surface. 

 (3) As Prof. Sollas himself remarks, it is difficult to account for 

 the peculiar branching form of Oldhamia. As it happens, during 

 the last two or three years I have seen many examples of 

 puckered phyllites, but never met with anything like Oldhamia. 

 This difficulty in the case of O. anliqua seems to me almost 

 insuperable. (4) In some cases I can detect two ^ets of mark- 

 ings crossing one another, so that the surface of the stone shows 

 a reticulate structure, one set of lines being less definite than the 

 other. This looks very much as if one branch of an organism 

 were lying on the top of another ; but I cannot account for it by 

 mechanical movements alone. (5) The constancy of char.acter 

 in the markings is also a difficulty. One would e.xpect every 

 stage of development from the least to the most imitative. 

 Now, though the Oldhamia is often indistinct, it certainly seems 

 to me more like bad preservation than imperfect development of 

 a structure. 



Of course I do not in the least question the accuracy of the 

 observations made by Mr. Teall and Prof. Sollas on the struc- 

 ture of the Bray Head rock ; I only doubt whether the relation 

 of this to Oldhamia can be'regarded as proved. However, I 

 am having some slides prepared from the above-named speci- 

 mens, and hope that they may help in solving my difficulties. 



23 Denning Road, N.W., April 5 T. G. BoNNEY 



Disappearance of Bishop's Ring in Colorado 



The reddish ring about the sun first distinctly appeared hers 

 (at the base of Pike's Peak) on November 22, 1883. For 

 several days before that date, a faint discoloration of the region 

 about the sun had attracted my attention. This gradually grew 

 more intense, and, on the day mentioned, became unmistakable. 

 The subsequent history of Bishop's ring as seen at this place 

 is, in brief, as follows : — 



The colour was most intense during the winter of 1883-84, 

 and diminished in brightness from that time until its disappear- 

 ance. At first it was visible almost all the time. Later, it 

 appeared only at the time of cold storms, which were accom- 

 panied by great vertical movement of the air, or when, for any 

 reason, the clouds reached to a great height. It was, on the 

 average, brighter during the winters than in the summers ; also, 

 it was brighter when the sun was near the horizon. Many times 

 in cold weather there has been not a trace of the ring, although 

 the air was so clear that peaks a hundred miles distant were dis- 

 tinctly visible from the heights behind this city. At other times the 

 ring has been very bright when the air was so hazy that the 

 mountains only ten miles away were hardly visible. During the 

 later months of 1SS5 it was invisible most of the time, but sud- 

 denly flamed out in wonderful intensity at the time of the great 

 norther of January 9-1 1, 1S86. Then for about two'months it 

 frequently appeared in the morning, or towards evening. During 

 the warm months of 1886 it was not seen. On October 15 it 

 appeared distinctly. About a week later it appeared very faintly 

 a few times, and since then I have not been able to see a trace 

 of it. My observations have been made at elevations of from 

 6000 to about 13,000 feet, and there was but little apparent dif- 

 ference in intensity at the different elevations. It is well known 

 that the atmosphere here is, in general, very dry and transparent. 



The diffraction-ring was often more coppery, almost rosy, in 

 tint at the time of the northers, and in the thickening haze in 

 the upper air preparatory to hailstorms. The great intensity of 

 the colour at such times, and its peculiar tint, and that, too, 

 irrespective of the amount of haze in the lower atmosphere, 

 makes it probable that the ring was in part due to diffraction on 

 ice-particles. If so, the ice-particles may themselves have been 

 due to precipitation on dust-particles. The fact that no diffrac- 

 tion-ring has been seen around the sun during the past winter is 

 not conclusive, for we have had no great northers, the season being 

 unusually mild. But the disappearance of Bishop's ring for so 

 long a time makes it certain that, even if there can be a circum- 

 solar glow due to diffraction on ice-particles, yet the proper 

 conditions for such a ring are realised only rarely, except when 

 there is a great amount of volcanic dust in the air. 



Colorado College, Colorado Springs G. H. Stone 



Iridescent Clouds 



Several brilliant displays of iridescent clouds have appeared 

 here during the past winter. One, on January 19, lasted for 

 more than two hours during a " Chinook" wind. A mass of 

 closely-connected cirro-cumulus clouds formed at a great eleva- 

 tion directly over the eastern base of the Rocky Mountains, and 

 thence extended eastward as far as the eye could reach. The 

 western sky was clear. As the clouds drifted slowly eastward, 

 new clouds formed along their western border. The western 

 limit of the clouds was for several hours nearly stationary, then 

 slowly advanced westward opposite the direction of cloud- 

 motion. Along the western border of the clouds were many 

 projecting tongues of cloud. At one time I counted seven com- 

 plete spectra at the thinner parts of the clouds— all showing 

 bands of red, green, and violet. There were also about twenty- 

 five spectra showing only one or two of the colours. The larger 

 of these iridescent spots were about lo° in diameter, and 'hey 

 varied in distance from 5° to more than 45° from the sun. Their 

 tints were intensely brilliant. There were also great numbers 

 of minute iridescent spots where the colours were in great con- 

 fusion—a phenomenon which is very common here. They 

 sometimes are so numerous as to simulate Bishop's ring. 



Colorado Springs, Colorado G. H. Stone 



A Claim of Priority 



In connexion with the letter of M. Ventosa headed as above 



in your issue of March 31 (p. 513), I should be glad if you 



would let me refer to a note which was appended to my paper 



