l82 



NA TURE 



[June 20, 1901 



when in flood, or 79 lb. to a cubic foot equal to i/Soth part 

 in weight of the water in the tubes. 



Both sea water and water saturated with ordinary salt were 

 tried, the latter in the proportion of one pound of salt to a cubic 

 foot. There was no apprecial)Ie difterence between these. 



The samples were placed in gl.iss test-tubes i foot long and 

 \ inch in diameter, filled with clean water up to the ten inch 

 mark. 



The material was well shaken and incorporated with the water, 

 and the time given forsettling is that taken by the particles to settle 

 through 10 inches and become visible in a solid form at the 

 bottom of the tube, and when no more particles could be dis- 

 cerned as settling when the tube was held up to the light. 



The column "water clear " is that in which the water in the 

 tube had become sufficiently transparent for black marks on a 

 white ground to be discerned through it. 



Practically all solid matter had settled in the time given in 

 the first column. The quantity deposited between the interval 

 of "settling" and "clear" was almost inappreciable, but still 

 sufficient to keep the water discoloured. With the specimens 

 containing the coarser material the water became bright again in 

 the time given in the second column, but with the very fine 

 material intervals varying from two to three hours up to as many 

 days elapsed before the water became as bright as it was before 

 the solid matter was added, partly depending on the fineness of 

 the material, but due more to the staining quality of some of the 

 ingredients contained in the sample. Thus the material taken 

 from Tilbury Dock Basin turned the water a black colour which 

 took some time to clear. The salt water took much longer to 

 become bright again than the fresh. 



Samples were selected as fairly representing the material 

 brought down in suspension by rivers, or eroded from the sea 

 cliffs, and deposited either in the form of salt marshes or trans- 

 ported to the bed of the sea. 



Thus numbers i and 2 represent the sand found on the 

 foreshores of the sea coast and covered at every tide ; 3 and 4, 

 material derived from chalk cliffs ; 5 and 6, the material in sus- 

 pension in the rivers Ouse and Trent, of which the Warp 

 lands bordering on those rivers are composed, 5 being the 

 material first deposited and near the river, and 6 that further 

 away where the water remains quiescent for some time ; 7 and S 

 represent the material of which salt marshes are composed, 7 

 being the silt deposited on the sand, and on which, when it rises 

 to about neap tide level, 6'68 above ordnance datum, samphire 

 begins to grow, 8 the finer warp deposited from about the level of 

 mean high water to that of ordinary spring tides, or io'2i to I3'34 

 above ordnance datum, on which salt water grass grows; 9 is 

 alluvial matter chiefly derived from the erosion of clay banks, 

 brought up by the tides and deposited in Boston Dock, whence 

 it was dredged, elevated from the barges and discharged with a 

 current of water on to low land, the sanjple being taken at the 

 part furthest away from the place of deposit ; 10 was taken 

 from the " batches " on the banks of the river Parrett at about 

 half-tide level of spring tides, or 13 '67 above ordnance datum, 

 where the finest part of the alluvium in the river settles and 

 which is collected for making bath bricks ; : i was taken from 

 Tilbury Dock Basin on the Thames when the water was being 

 stirred up by the eroding pumps ; 12 is from clay used for 

 brick making ; 30 per cent, of the particles of this material were 

 from i/8ooth to i/ioooth inch in diameter and the remainder 

 smaller than this, the average size being 1/1600 of an inch. 



W. H. Wheeler. 



The Subjective Lowering of Pitch. 



Ik the subjective effect described by Mr. E. Hurren Harding 

 (ante, p. 103) is of general occurrence, it is contrary to what 

 one might e.vpect from the observation of singers. 



It is well known that persons with a good ear may sing flat, 

 being unconscious of the defect, though they would notice it 

 immediately in other singers. From this it seems that the 

 singer's voice sounds higher to himself than to others, and yet 

 it is louder to him than to any one else. Sharp-singing, on 

 the other hand, is regarded as more indicative of a defective 

 ear. 



I have no large tuning-forks at hand, but with ordinary 

 forks and the sound-board of a piano I find that, on bringing the 

 ear close to the source of sound, the sense of pitch is not altered, 

 though the elements of noise are added to the sound ; and these 

 elements consist mostly of vibrations of lower pitch, presumably 

 the proper notes of parts of the auditory apparatus. 



NO. 165 I, VOL. 64] 



In connection with this subject it may be noted that, owing 

 to the structure of the cochlea, vibrations of small ariiplitude 

 affect chiefly the lower part of its spiral : and that as the 

 amplitude increases (independently of pitch?) the concussion 

 reaches further up the spiral, where the fibres of the basilar 

 membrane are longer than in the lower part, and therefore more 

 responsive to slower vibrations. F. J. Ali.en. 



Malvern, June 9. 



With reference to Mr. Harding's letter (p. 103), it would be 

 interesting to know whether the effect he has observed with the 

 voice, with tuning-forks and with organ pipescan also be obtained 

 from a siren. G. W. Hemming. 



Yes ; such eft'ect can be obtained from a siren. If a siren be 

 so rotated as to give a note approximating to middle C, the note 

 appears flattened when the ear is placed close to the instrument, 

 such flattening being estimated by dift'erent observers (at different 

 times) as from a semitone to a whole tone. 



Normal College, Bangor. E. HuRREN Harding. 



THE NATIONAL ANTARCTIC EXPEDITION. 



"XT O answer, so far as we are aware, has appeared to 

 ■'■ ' Prof. Poulton's letter to the Fellows of the Royal 

 Society on Prof. Gregory's resignation of the leadership 

 of the scientific staff of the Antarctic expedition (of 

 which we published a copy on May 23). We are there- 

 fore forced to conclude that the representatives of this 

 Society on the Joint Committee are content (to use our 

 own words) to let judgment go by default, and admit 

 Prof. Poulton's statements to be substantially correct. 

 Since that date, according to a second letter which we 

 published last week, rumours have been circulated that 

 the real cause of Prof. Gregory's resignation was not 

 that which had been publicly stated, but domestic con- 

 siderations. The dates given to Prof. Poulton's state- 

 ments and e.\tracts from letters written by Prof. Gregory 

 (which documents we have been allowed to examine) 

 show these rumours to be baseless, and how they 

 have arisen is no less a mystery than that alteration 

 in the minutes of a resolution passed by the Joint 

 Committee on February 14, 1900, mentioned in Prof. 

 Poulton's former letter. Prof. Gregory's position has 

 been consistent and definite throughout. He accepted 

 the offer of the post on certain conditions, which he be- 

 lieved himself (not unreasonably, in our opinion) to have 

 made clear. On returning to England last December 

 he found the situation had been altered. Though not 

 liking the changes he decided to accept them, and natur- 

 ally supposed when he left England last February that 

 the arrangement, concluded the day before he sailed, 

 w-ould be final. On receipt of a cable message that it had 

 been further modified (by the acceptance, in substance, of 

 Mr. Darwin's proposition), his first impulse, as he states, 

 when the news arrived was to send a telegram an- 

 nouncing his resignation ; but, after retlection, he thought 

 it wiser to await the receipt of particulars by letter. Then 

 came the refusal of the Council of the Royal Geographical 

 Society to accept the instructions, thus modified, the 

 appointment of an arbitration committee, as we may call 

 it, and their decision, which virtually endorsed the action 

 of that Society. When Prof. Gregory was informed by 

 telegraph of the last step he at once cabled his resigna- 

 tion. 'We do not see how he could have done otherwise. 

 There was now, to use his own words, " no guarantee to 

 prevent the scientific work from being subordinated to 

 naval adventure, an object admirable in itself, but not 

 the one for which I understood this expedition to be 

 organised." 



Prof. Gregory, some experts have pleaded, is unreason- 

 able in his expectations ; the rules of the Service 

 necessitate the complete autocracy of the naval officer in 

 command. We content ourselves with the reply that if 



