584 



NA TURE 



{Oct. 2 1, 1880 



and floating icebergs, and all the country .south of it above water 

 and clear of those influences. Since then the large gi-anite 

 boulder on the shore of Barnstaple Bay, estimated to wei^h ten 

 tons, has been brought more prominently under our notice by 

 Mr. W. Pengelly (Trans. Dev. Assoc, vi. 211), and several 

 others by Mr. T. M. Hall (Id. xi. 429), discovered by excava- 

 tion. All these are travelled blocks, and probably ice-borne. 

 Many attempts have been made by ardent and intelligent students 

 of late years to detect proofs of glacial action further south, and 

 even to the shores of the British Channel, but hitherto with 

 doubtful success. There lies on the greensand of Haldon, near 

 Exeter, and on the Blackdown Mills, stretching away towards 

 the south-east corner of the county of Devon, a stratum of tough 

 yellow clay full of white flints, mostly angular. About Haldon 

 and eastward over Pitminster and Churchstanton, many white 

 quartz rounded pebbles, foreign to the accompanying beds, are 

 met with. Farther south, between Honiton and the sea, this 

 stratum of flints and clay in some places is seen to be from forty 

 to fifty feet thick, and the best section of it is in the gravel pits 

 near the clifton Peak Hill, on the west of Sidmouth. By some 

 persons this deposit has been regarded as the thinned-outedge of 

 the plastic clay formation, containing the remaining flints of the 

 washed-out chalk, still found more perfect at Beer Head, a few 

 miles east. Whether it was this, or whether it was a boulder 

 clay, so called, it is well to remark that, though thickest on the 

 flat tops of the hills, it seems to lap down over their sides, as if 

 it had been deposited after the valleys and the elevations had 

 come to their present conformation ; and at two places at least to 

 be visible in the valley of Sidmouth — one under the great blocks 

 of breccia in the orchard near tlie brook on the Boomer or 

 Boughmoor Estate, and the other on a subordinate hill in a grass 

 field, at about 200 yards from Jenny Pine's Corner, walking 

 down the new road towards Cotmaton, and on the right-hand 

 side. Most of tliis latter patch of clay and flints was dug away 

 two or three years ago to assist in forming the new road. 



When engaged in making certain trenches and excavations on 

 the top of Salcombe Hill in 1S79 fir archxological purposes 

 (see Procecd'uigs Soc. Antiq. Lon. viii. 209) it appeared that the 

 yellow clay, to the depth ef two or three feet, was not so much 

 encumbered with flints as deeper down. But whilst thus engaged, 

 what struck me as rather strange was that numerous fragments 

 of black peat were more or less generally but irregularly distri- 

 buted^ through the upper two feet ; and bearing in mind Mr. 

 Nield's letter, I have in my foregoing remarks been trying to 

 lead up to this point. Tlie cases may not be similar, but they 

 are v.orth comparing. The land on the top of the hill at this 

 place still bears its wild growth of heath and furze, and has never 

 been subjected to the plough or io cultivation of any sort ; so 

 that the clay has not bfcn disturbed by the hand of man. It is 

 too soon to say that this capping of clay and flints is of glacial 

 origin ; but some of the indications that have suggested the idea 

 may be observed in the section in the gravel pils on Peak Hill, 

 especially when fresh dug down. They are : (i) that no hori- 

 zontal bedding is visible, as there would be if the deposit had 

 been made in a large body of undisturbed water ; (2) That, on 

 the contrary, waving and distorted lines are sometimes very 

 plain, one instance of which I carefully sketched and coloured in 

 January, 1875 ; (3) and that the long axes of the embedded 

 flmts do not ai a rule lie horizontally, as they would necessarily 

 do if they had settled at the bottom of a sea or pond, just as an 

 egg will lie on its side, and not on its point, but they are distri- 

 buted through the soft mass at all angles, as raisins lie in a 

 pudding that has been kueaded up together. 



My object in this communication has been merely to compare 

 the case of the peat mixed with the clay on Salcombe Hill with 

 the somewhat similar case occurring near Oldham. 



^, , „, , P.O.Hutchinson 



Did Chancel, Sidmouth, Devon, October 4 



In Nature, vol. xxii. p. 511, I find a letter from Mr. G. H. 

 Morton, in which he expresses an opinion contrary to that ex- 

 pressed by me (vol. xxii. p. 460), as to the age of the " peat bed 

 in the drift of Oldham." The section therein alluded to is fairly 

 described by him, but I am surprised that he should for an 

 instant entertain the belief that the clay "has simply slipped 

 down off the sand on to the surface of the peat at a lower level." 

 Had the clay slipped down we ought to have been able to see 

 some indications of the conjectured displacement. Let me say, 

 noweyer, that during my repeated visits to the place and my 

 examinations of the section I have utterly failed to perceive any 



trace of such indications, and, moreover, I do not remember that 

 one person out of some scores who have in presence of the section 

 pointed out to me the slightest appearance of disturbance. There 

 is not a broken or crumpled line in the whole section. 



The peat bed, and indeed the whole of the section, is now, I 

 am sorry to say, covered up ; but in and about Oldham we have 

 a large area covered by what I believe to be typical beds of the 

 "Middle" and the bottom of the Upper Drift— alternations of 

 gravel, pebbles, fine and coarse sand, the latter showing lines of 

 "current bedding," and occasionally clay with boulders— in 

 which many similar sections, but wanting in the peat, of course, 

 may be seen, and in which the position and surroundings of the 

 beds quite forbid the possibility of "slipping," The idea of 

 the upper clay "having been excavated and thrown down" is, 

 I think, too improbable to be seriously entertained, seeing that 

 the surface-soil and subsoil on the top of it are of the usual 

 thickness common to the neighbourhood. 



The "blue silt" alluded to by Mr. Morton as giving strength 

 to his suspicions, I can assure him is one of the supports upon 

 which 1 rest my opinion that there has been no disturbance. 

 Do I understand him to mean that the silt is the result of the 

 washings of some passing stream? If so, let me recommend 

 him to visit the railway cutting across the large peat bog a few 

 miles from here, and known as the " Ashton Moss," where he 

 will find, at the bottom of a bed of recent peat, of from two to 

 three yards in thickness, a thicker, but in every other respect a 

 similar band of blue silt, upon which the peat rests throughout 

 the length of the whole cutting. This silt seems to have its 

 ejuivalent in the "floor clay" which accompanies our seams of 

 coal. I believe that tlie removal of so much of the peat bed and 

 drift deposits from the face of the excavation as has already 

 taken place has served all the purposes of the "few hours 

 digging at a right angle to the present exposure," suggested by 

 Mr. Morton. 



Perhaps a more complete acquaintance with the Oldham drift 

 beds would bring Mr. Morton nearer to my way of thinking. I 

 shall be glad to see him here again, and to assist him in making 

 a wider, and more thorough examination of them. 



29, Radclyffe Street, Oldham, October 7 James Nield 



Temperature of the Breath 



Mr. McNally has, it appears to me, missed the point of my 

 observations on this subject. 



His own experiments, though they show a temperature ob- 

 tained by breathing on a thermometer through silk, wool, and 

 linen, considerably above the accepted temperature of the breath, 

 are by no means an exact repetition of mine. He only breathed 

 through four folds of the material for three minutes. I breathed 

 through a much greater amount of material and for a longer 

 lime, viz,, twenty to thirty folds tightly encircling the thermo- 

 meter bulb for five minutes. 



The temperatures I obtained were very much higher than 

 those observed by your correspondent. Thus on a warm summer 

 day the temperature obtained on rising in the morning before 

 dressing and before eating was 106°. In the afternoon, after 

 playing a game of golf, when returning home by rail with all 

 the windows open, the temperature observed was 107°. The 

 same day, after dinner (without alcoholic stimulants), the ther- 

 mometer rose to loS" when breathed on in the way described. 

 The temperature of the air that day averaged 70°. Since then 

 I have not obtained a higher temperature than io7""5. 



These temperatures were obtained by breathing through a silk 

 ]30cket-handkerchief tightly rolled round the thermometer, but I 

 have obtained temperatures nearly as high when the thermometer 

 was wrapped up in cotton or woollen stuff. 



Mr. McNally asserts that the explanation suggested by my 

 friend that the high temperature thus obtained was owing to the 

 heat evolved by the condensation of the aqueous vapour con- 

 tained in. the breath is "undoubtedly correct," but he gives no 

 answer to the obvious objection to this explanation, viz., that if 

 the real temperature of the breath be, as stated in physiological 

 works, 95° to 97°, condensation of the aqueous v.ipour in it 

 would only take place as long as the material through which 

 it is propelled was of lower temperature than the breath. 

 When the material attained a higher temperature than 97° the 

 aqueous vapour, in place of being condensed, and thus evolving 

 heat, would be still further evaporated, and hence be a cause of 

 reduction of temperature. 



The fact that woollen clothing prevents chill after exercise has 



