502 



NA rURE 



\_March 27, 1884 



.i|)peared wholly nebulous, with a bright central condensation ; 

 the tail broad, but faint. I could only trace it some 2" or 3°. 

 The brightness of the nucleus must have been considerable, as 

 when close to the horizon I could see it through a pretty thick 

 cloud. Subsequently the nucleus has seemed to me decidedly 

 more disk-like, I suppose from being better seen. I may add 

 that the sunset-glows and the unusually cloudy weather we are 

 having have interfered greatly with s.ilisfactory observation. 

 Nelson, N.Z., February i A. ,S. Atkinson 



The Access to Mountains and Moorlands Bill 



I AM glad to observe that you have called the attention of 

 scientific men to the importance of Mr. Bryce's Bill. Perhaps 

 nothing can better show the need of such a measure than certain 

 facts in regard to the Clova district in Forfar.shire, which is classic 

 ground to the botanist ; indeed, I think I may venture to say 

 that it is the richest ground in the British Islands. From time 

 immemorial a right of way existed through Glen Dale, and, I 

 can remember the time when botanists could ascend any of tlie 

 hills in that district without being subjected to the tender, though 

 somewhat embarras-iiig attention of gamekeepers. I have goad 

 reason to believe that the case is somewhat altered in recent 

 years, and that, after a man has gone hundreds of miles in order 

 to see Oxytropis camf-cslris growing in its only British station, 

 he may find him=elf turned back just within sight of the goal. 

 The thing can still be done by taking advantage of a curious 

 fact in natural history, viz. that two gamekeepers cannot remain 

 long in loving converse with three men : by keeping this fact in 

 mind, one out of three may still study thebDtany of Clova. 

 After having gone pretty well over Scotland I am glad to say 

 that there are many places in which there is no need for 

 Mr. Bryce's Bill. In most cases in which it is needed it is where 

 "liew men" usurp a power which the old lords of the soil 

 never dreamt they possessed. A. Craig- Christie 



Edinburgh, March 24 



A Sixth Sense 



In the valuable address given by Sir William Thomson at the 

 Ivf idland Institute, Birmingham, on October 3, and reported so 

 fully in the columns of N.\ture, it is implied that Dr. Thomas 

 Reid of Glasgow brought out the distinction of a si.xth or muscu- 

 lar sense. I cannot find any satisfactory evidence of this, al- 

 though Reid came very near it indeed when he stated in his 

 "Inquiry into the Human Mind," chap. v. section i : — "By 

 touch we perceive not one quality only, but many, and those of 

 very different kinds ; " and again : — " There is, no doubt, a sen- 

 sation by which we perceive a body to be hard or soft ; " and 

 again, farther on he even speaks of its being strange that this 

 sense should " be so much unknown as never to have been made 

 an object of thought or reflection nor to have been honoured 

 with a name in any language." 



And on the other hand, while I cannot detect any .Tttempt 

 whatever to refer this sensation to the muscles as its peripheral 

 origin, while speaking of our conception of the hardness of 

 bodies. Dr. Reid says (p. 121, ed. of 1846) : — " We have no 

 way of coming at this conception and belief, but by means of a 

 certain sensation of touch ; " and again, " I see nothing left but 

 to conclude that, by an original principle of cm- constitution, a 

 certain sensation of touch both suggests to the mind the concep- 

 tion of hardness and creates a belief of it." Reid, in short, like 

 his eminent predecessor Hutcheson in the same chair, was di- 

 satisfied with the ordinary division of the senses, and really 

 felt disposed to split up the varied phenomena bundled 

 up under the term "touch" into two or more divisions; 

 but it was reserved for Dr. Thomas Brown, a good physiologi^t 

 according to the light of the times, and Professor of Moral 

 Philosophy in Edinburgh (lSio-20), explicitly to complete 

 the distinction hinted at by Reid, and to refer our con- 

 ception of resistance or tension (as we find in estimating weights 

 by the hand) to a distinct sixth or muscular sense. Thus in his 

 twenty-second lecture he says : — " The feeling of resistance is, I 

 conceive, to be ascribed, not to an organ of touch, but to our 

 muscular frame, to which I have already more than once 

 directed your attention, as forming a distinct organ of sense." 

 In the lecture which follows that. Brown admits the frequent 

 min;^ling of mere tactoial sensation with that of muscular effort : — 

 " But it is not of this mere tactual feeling we think when we 

 term bodies hard or soft — it is of the greater or less resistance 

 w'hich they afford to our muscular contraction." 



. It is remarkable that the teaching of this eminent psychologist, 

 the preceptor of James Mill, should so early have been forgotten 

 in Scotland. Henry Faulds 



Laurel Bank, Shawlands, Glasgow, March 18 



Mr. Faui.ds, in the preceding letter, is no doubt quite cor- 

 rect in remarking that the distinction pointed out and insisted 

 on (not merely hinted at) by Thomas Reid, a little more than a 

 hundred years ago, in the Moral Philosophy Chair of the Uni- 

 versity of Glasgow, was more clearly and fully defined by his 

 eminent successor in Edinburgh, Thomas Brown. But I cannot 

 agree with his last sentence, implying that Thomas Brown is 

 forgotten in Scotland. In fact, my mind was so full of Reid 

 and Brown, from my recollections of the teachings of the Pro- 

 fessors of Moral Philosophy and Logic in this University, that, 

 in giving my address at Birmingham, I said Thomas Brown, 

 meaning Thomas Reid, but feeling the names of Keid and Brown 

 both thoroughly mixed up w ith all I had ever learned of this 

 subject. William Thomson 



The University, Glasgow, March 20 



Earthworms 



The theory of the formation of vegetable mould through the 

 action of earthworms, by Darwin, received little attention 

 when published from people who had been accustomed to 

 examine the soils of various countries. That the vegetable soil 

 had been formed as he states seemed to have been accepted by 

 his followers without hesitation. In your columns, however, of 

 late, letters have appeared from Messrs. R. M. Christy and T. 

 E. Wilcox, showing that earthworms do not exist in the prairies 

 in the north-west of Canada or in the United States, in those of 

 Kansas, the Indian Territory, or in Idaho and Washington 

 Territory. This is simply what may be expected. Notwith- 

 standing the keenness of observation of Darwin and his 

 width of observation, there seem vast regions where earthworms 

 have had little to do with the formation of the vegetaiile soil. In 

 many parts of Australia, and also in the moister climate of 

 New Zealand, the soil affords few indications that earthworms 

 ever passed it through their bodies. In a section of soil I 

 brought from the Mataura plain. South Island of New Zealand, 

 nothing could be seen to indicate that worms had ever swallowed 

 it. That vegetable soil forms a fit habitation for earthworms is 

 undoubted. Darwin admits "that a layer, though a thin 

 one, of fine earth, which probably long retains some moisture, 

 is in all cases necessary for their existence." Before this thin 

 layer existed, how could they — the worms — form vegetable soil? 

 This thin layer must have been formed in some other way ; 

 Darwin does not say how. It is not necessary to call in the aid 

 of earthworms to do so. The very name which has been uni- 

 versally applied to the thin upper covering, the exterior film en- 

 veloping the surface of the deposits underneath, viz. vegetable 

 soil, speaks to its origin in the decay of vegetation. Take for 

 instance the boulder-clays of this part of the Lothians in Scot- 

 land, with their tough, stony texture, their pebbles as finely 

 striated as when the ice squeezed them into the pasty mass of 

 crushed shales out of which they appear to have been partly 

 formed. While these surfaces could have afforded none of the 

 conditions required by Darwin, or indeed supply any odier save 

 inorganic food, the slow- growth on their su' faces of the more 

 simple forms of vegetable life, and their decay, would in the 

 lapse of ages supply the thin film which Darwin requires. It 

 surely, then, is attempting too much to .ascribe to the earthworm 

 the formation of the vegetable soil. The earthworm is not the 

 only occupant of the material which the growth and decay of 

 vegetation supplies as a surface covering. The earthworm is not 

 the only drainer. The roots of many plants not only descend 

 deeply into the subsoils, but also fetch up from dep'hs where 

 worms could not reach supplies of material to mix with the 

 superficial covering ; and so do the various insects which have 

 their habitat in the soil, burrowing as they go, and casting, like 

 the mole, the stuff behind them or upivards as they descend. 



So far as I have examined soils. I am inclined to think that 

 the earthworm is far more plentiful when a'limal matter in a 

 decaying state is applied to soils near the dwellings of man, or 

 when his deposits are laid over those of the larger animals. As 

 .against the views of Hutton and Playfair, and as stated by Darwin, 

 that the vegetable soil or mould is always dimiLiishing, I have to 

 say it seems entirely the reverse ; it seems to have had a be- 



