3o8 



NATURE 



\Atiojtst 4, 1 88 1 



into a'fork (/), with two .yellowish points; these points stan.l 

 close beneath the yellow anthers, whilst the apical apertures of 

 the red anthers (a-) are placed far below them near the stigma ; 

 also the style and tlie stigma (j^ are coloured to very like tlie 

 corolla, that from some di-,tance neither they nor the longer sta- 

 mens can be seen at all. Any large bee (like Xylocopa, Centris, 

 or Bombus), when working on the smaller anthers in order to 

 collect pollen, would, by moving the connective fork of the larger 

 ones, press the apertures of the latter against the ventral side of 

 its abdomen and powder it with pollen. Until now I have only 

 seen a little fly (Syrphidce) and Trigona ruficrus visiting tliis 

 flower, both too small to fertilise it. The fly lakes only notice of 

 the yellow anthers ; the Trigonas, too, always sit down first on 

 these ; but most of them (the more experienced specimens ?) turn 

 then round, and go to the larger anthers, which offer a more 

 copious pollen-store, and work on them with their mandibles or 

 eat them up entirely. Even if larger bees acted in the same 

 manner as Trigona ruficrus, they would have powdered the 

 ventral side of their abdomen before going to plunder the latter. 

 The pollen of both kinds of anthers is white." 



Hermann Muller 



Palaeolithic Implements in the Thames Valley at and 

 near London. Their Comparative Numbers 



In my former letters. Nature, vol. xxiii. p. 604, vol. xxiv. 

 p. 29, I cited instances of the occurrence of these objects at 

 great heights, indicating gi'eat antiquity, at the north and south 

 of London. After the positions of the implements on the 

 different old river terraces are considered, their number^, as 

 compared witli the amount of material excavated, is a subject of 

 considerable interest, as these numbers indicate in a broad way 

 the amount of human population. 



Before I give the results of my own experience I may 

 say here that I have had these implements in view for aljout 

 twenty years. I have not searched for them myself during all 

 this time, although at first I commonly looked over pits and 

 roads for implements and flakes with little or no result. 



I had four reasons for beginning a thorough examination of 

 the London gravels : — I. I had long taken a great interest in the 

 subject. 2. I had particularly noticed the implement found in 

 Gray's Inn Lane now in the British Museum, I had looked over 

 Col. A. Lane Fox's collection from Acton and Ealing, and I 

 knew of two implements from the gravels excavated near my 

 own house. 3. I felt disappointed at not meeting with Thames 

 valley implements myself. 4. I had been unwell through over- 

 work, and my doctor told me I should not be well again till I 

 regularly took a four-miles daily walk. 



In the early spring of 187S I determined to walk over the 

 London gravels and note the constituent stones — not walk ^iver 

 the roads and pits once or twice, but ten, twenty, or if need be 

 fifty times, so as to thoroughly acquaint myself witli the 

 stratification and materials. 



I began in May, 1878, to examine the excavated gravel at 

 Clapton, N.E. London, in the valley of the Lea. Here, after 

 considerable searching, I found an implement and several flakes. 

 I then mapped out the gravels for tuenty-seveu miles in a line 

 east and west of North London, and wherever the gravel has 

 been exposed in these twenty-seven miles I have been over it a 

 great number of times. In three years — from May, 1878, to May, 

 1881, I found exactly one hundred implements, mostly Ungulate 

 examples (a few ovate), and thirteen trimmed flakes, i.e. genuine 

 implements, but worked on one face only. This is equal to one 

 hundred and thirteen perfect specimens. I also found twenty- 

 one butt-ends and six points, some broken in Palaeolithic times, 

 others showing modern fractures ; side-scrapers, six; flakes about 

 one thousand four hundred ; broken fossil bones, teeth, and 

 tusks, chiefly mammoth and horse, not uncommon. Hammer- 

 stones of quartzite, with abraded ends, none. An unabradcd 

 quartzite pebble, such as the pebble mentioned by Mr. Perceval, 

 teaches nothing. Even if one end is abraded off, it might have 

 been rubbed off by other pebbles passing over it whilst naturally 

 fixed in the bed of a stream. When both ends of a quartzite 

 pebble are abraded quite away, and the abraded parts are of a 

 distinctly different colour from the rest of the pebble, such a stone 

 is probably a hammer-stone. I have several genuine examples 

 of these of Palceolithic age, but not from the Thames valley. 



On reading these notes some persons may be inclined to 

 exclaim. What a large number of implements ! How common 

 these objects must be! My reply is they are by no means 

 common, but as a rule extremely rare and most difficult to find. 



One seldom sees a first-class implement resting flat and clean in 

 the middle of a road or pit, inviting the passer-by to pick it up. 

 They are usually half-buried, with only part of the point, edge, 

 or butt visible, and that part frequently covered i\'ith clay or dirt, 

 so that it requires a sharp and trained eye to distinguish the 

 implements and flakes from the ballast with which they are 

 incorporated. 



My first attempts were to find how many implements occurred 

 in a hundred tons of London gravel, but I found it impossible to 

 determine this with certainty ; I however could accurately find 

 how many miles of the actual drift I had walked over, and my 

 experience is that I walked in three years over four thou^nd 

 five hundred miles of gravel to find one hundred and thirteen 

 implements, equal to a walk of about forty miles for one 

 implement. 



Of course the implements may be more frequent in some 

 places, as at Milford Hill, Salisbury, and Warren Hill, Milden- 

 hall, and much less frequent in others, but the above statement 

 is my personal experience in the twenty-seven miles of river- 

 gravel to the north of the Thames at London. The men work- 

 ing in the roads and pits often questioned me, and I set all the 

 men to look for the implements during my absence : the whole 

 of the mfu together in three years produced twenty-two extra 

 implements, ovate or Ungulate, and worked on both sides. 



The mere accumulation of implements was by no means my 

 object. I felt from the first that to entirely depend upon work- 

 men was a great mistake, as all ill-defined instruments must be 

 lost. I therefore personally looked out for genuine new things, 

 and especially wished to ascertain, if possible, what the implements 

 themselves had to teach of the men who made them, how the 

 implements were deposited, and if possible to calculate their 

 age in years. With these objects in view I have kept a manu- 

 script book, giving the exact circumstances of finding of every 

 implement in my collection, not only in reference to the imple- 

 ments belonging to the Thames Valley, but to nearly all the 

 implementiferous river-valleys of this country. With equal care 

 I have kept a list of non-implementiferous positions, and my 

 experience is, the lower gravels of the Thames as at Hammer- 

 smith and Battersea are barren. As soon however as a seventy 

 or eighty feet terrace is reached, the implements and flakes crop 

 up. Two implements have been found in the Thames at Ham- 

 mersmith and Battersea, as recorded by Mr. Evans ("Stone 

 Implements," p. 52S), but these, of course, were washed out of 

 a higher bed. I have found several flakes and an implement at 

 Clapham Common and Battersea Rise, but here the heights are 

 seventy to ninety feet. The most persistent searching at Lower 

 Battersea and Hammersmith has produced with me absolutely 

 nothing. With your permission I will give further rendts in a 

 future letter. Worthington G. Smith 



125, Grosvenor Road, Highbury, N. 



THE COMET 



WE have received the following further communica- 

 tions on the lately-visible comet : — 



The appearance of a large comet has afforded an 

 opportunity of adding to our knowledge of these bodies 

 by applying to it a new means of research. Owing 

 to the recent progress in photography it was to be hoped 

 that photographs of the comet and even of its spectrum 

 might be obtained and peculiarities invisible to the eye 

 detected. For such experiments my observatory was 

 prepared, because for many years its resources have been 

 directed to the more delicate branches of celestial photo- 

 graphy and spectroscopy, such as photography of stellar 

 spectra and of the ncbulse. More than a hundred photo- 

 graphs of spectra of stars have been taken, and in the 

 nebula of Orion details equal in faintness to stars of the 

 147 magnitude have been photographed. 



It was obvious that if the comet could be photographed 

 by less than an hour's exposure there would be a chance W\ 

 of obtaining a photograph of the spectrum of the coma, {| 

 especially as it was probable that its ultra-violet region 

 consisted of but few lines. In examining my photographs 

 of the spectrum of the voltaic arc, a strong band or group 

 of lines was found above H, and on the hypothesis that the 

 incandescent vapour of a carbon compound exists in 



