. oe 
+ 
- 
lighting, and their elasticity varied in almost the same proportion 
_ as their susceptibility to change of resistance from stress, so that, 
the alteration of resistance divided by the strain produced, 
ranged in the five specimens between the limits 2°144 and 2°835. 
The corresponding numbers in the case of most pure metals 
(aluminium is an exception) are greafer than these, and in the 
case of nickel, with which metal curiously enough the effect of 
_ moderate longitudinal traction is to decrease the resistance, the 
_ alteration of conductivity is ch greater. 
ie ote! will, be observed from the numbers given above that the 
minution of resistance which can be produced in carbon by 
_ pressure is very slight, so much so indeed that if we could 
__ compress a carbon rod to /a/f its original length, the resistance 
4 _ would not be diminished to one-third of the original resistance, 
r and that therefore the amount of compression which can be 
really produced without danger of breakage causes such a slight 
decrease of resistence as requires special precautions and a good 
-galvanometer if this decrease is to be measured with any accuracy. 
King’s College, Strand, March 7 HERBERT TOMLINSON 
a Paleolithic Floors 
In reference to this subject, as adverted to by Mr. W. J. 
Knowles, Nature, vol. xxv. p. 409,—-several Paleolithic 
_  working-places, floors, or old land surfaces have been described. 
- With some of these surfaces, I am slightly acquainted, and 
with one of them I am we// acquainted, as it was discovered by 
myself in London, in 1877—8. ‘This surface is in the Valley of 
_ the Hackney Brook, an affluent of the Lea, which in its turn is 
( a northern tributary of the Thames. ‘The course of the Hackney 
Brook is illustrated in the No. of NaTurE (p. 417) which 
) contains Mr. Knowles’ letter ; when excavations are made in this 
-- valley, Palzolithic implements and flakes are disinterred, which 
in some instances belong to the Thames and are very ancient, in 
thers to the Lea and probably somewhat less ancient, whilst a 
_ third set of implements belong to the Hackney Brook, and 
' undoubtedly date from a very recent period of the Palzolithic 
age. In the surface humus of the Lea near the Hackney Brook, 
- Neolithic celts, polished and unpolished are also found with 
‘flakes of the same age. 
When I first found Palzolithic implements in the gravel, sands 
and loam of north-east London, I was greatly puzzled by some 
- of the examples being considerably abraded, whilst others were 
-as sharp as if just made. The sharp examples belong to one 
‘stratum and the abraded specimens to a totally different one. 
The explanation of the abraded and unabraded examples rests 
in the fact that near the Hackney Brook most of the gravel 
is about ten or twelve feet below the surface, but this Thames 
| gravel and its contained abraded implements has nothing 
. whatever to do with the Hackney Brook, the old banks of 
~ which are about four or five feet below the present surface, and 
: ‘on these banks (which I have examined in the stream’s course 
or three quarters of a mile, north and south at Stoke New- 
_ ington, and Shacklewell) there lived at one time a considerable 
-_-eolony of Palzeolithic men. The floor upon which this colony 
of men lived and made their implements has remained undis- 
~ turbed till modern times and the tools, together with thousands 
of flakes, all as sharp as knives, still rest on the old bank of the 
brook just as they were left in Palzolithic times. In some places 
‘the tools are covered with sand, but usually with four or five feet 
of brick-earth ; the sand when it occurs is full of the shells of 
fresh-water molluscs. 
The floor is exposed in digging for the foundations of houses, 
- it is sometimes visible as a dark line only at the base of the 
Joam ; at other times by the presence of a few inches of gravel ; 
occasionally the traces of the floor are obliterated. All the im- 
; plements from this floor are as sharp as on the day they 
Were made, a few are dull in colour, the majority are 
lustrous, a few are whitish from their long contact with 
clay, but though the surface of the implements is whitened 
by decomposition, yet the tools remain perfectly sharp. As 
a rule the implements of the Hackney Brook are small in 
size, beautifully made, and extremely neat, some rivalling in 
_ exquisite workmanship the best Neolithic work: scrapers 
are fairly common, but not of the horse-shoe form. Were the 
makers of these tools the same with the men of some of the 
caves? the evidence seems to point in that direction, ‘‘ Cave- 
men” could not always have been in caves, surely some of these 
‘© Cave-men ” lived in communities in the open air, and it seems 
clear that if we are to find intermediate links between Palzoli-° 
thicand Neolithic times we must not confine ourselves to caves 
- 
aaa Sere 
NATURE 
but search for traces in positions like the comparatively mod Ns 
Valley of the Hackney Brook. ne 
It appears to me that these minor tributaries of great rivers 
haye never been properly searched. Geologically considered, the j 
Thames with its gravel and implements must be extremely ancient. 
whilst the shallow unimportant Hackney Brook must be com-— 
paratively modern. In these minor affluents then we have 
traces of the more recent cohorts of Paleolithic men, and the 
tools that are found, seem, by their style of workmanship, to 
prove their comparatively recent date.—Recent as that date may — 
be however, I consider it to be far older than the times when 
the lower terraces of the Thames were laid down, for in these 
lower gravels, implements and flakes (with the exceptionof some _ 
stray example now and then, that has been washed down from a 
higher position) are absent. , P 
Any person is at liberty to look over the things Ihave got 
from this place, but at present I do not wish for the number of 
the tools to be further reduced by gifts or exchanges. Many 
objects I have already given away, but, for a time, at any rate, 
I wish to keep the things together, as they teach a better lesson 
in company than when distributed in different collections, As 
for the simple flakes, whether sharp and belonging to the till 
now undisturbed Palzeolithic floor of the Hackney Brook, or 
abraded and belonging to the deeper excavations exposing the ~ 
old terrace of the Thames, any one is welcome to any number 
of examples of these from me, and I am willing to send them as 
gifts to anyone, provided I am not put to expense in transit. " 
At the present time the Paleolithic floor is to be seen in 
section in several places, and I will conclude by mentioning 
one, On the north side of Stoke Newington Common, (nearest 
point, Stoke Newington Railway Station, from Liverpool 
Street) there are four new roads ; the easternmost road is named 
Fountayne Road, and is marked on Stanford’s Library Map of - 
London. At the extreme south eid of Fountayne Road, z.e, the 
Stoke Newington Common end, on the east side, shallow 
foundations of about four feet have been dug for a few new 
villas ; now, if the two or three northernmost of these shallow 
excavations are looked into at a de th of about three feet, a thin 
stratum of gravel, a few inches only in thickness, will be seen 
sloping southwards into the (here filled in) Hackney Brook. 
This is the floor upon which the Paleolithic men once walked, 
lived, and made their tools. In the excavation for the two 
northernmost villas I recently saw the loam carefully removed, and 
on this spot two pointed Palzolithic implements (one amongstthe 
best of my collection) were found, the first black and lustrous, : 
the other buff, mottled with white from long contact with the 
loam, and lustrous, both as sharp as knives; they were picked 7 
up with numerous flakes on the very spot where they were 
originally laid down by their Palaeolithic owner or owners. 
A word of warning to visitors. After I published my ~ 
localities in 1868, certain persons went to the places mentioned, D 
and offered large sums of money to the men for implements and _ 
flakes ; in this case, the unfortunate re-ult was, that the men 
and boys of this spot soon found that they could strike off flakes ‘ 
and even make implements sufficiently near to deceive ‘avid 
but unwary collectors.” Therefore, unless any visitor instantly 
knows at sight (which is quite easy) a genuine implement or 
flake from one made on the spot, let him buy nothing of the 
boys or men without first consulting the writer of this note. 
: WorTHINGTON GEO. SMITH 
125, Grosvenor Road, Highbury, N. 
a 
- 
In Nature, vol. xxv. p. 449, you quote an account from 
Naturen of the changes of movement observed in Norwegian 
glaciers. In this it is stated that the great Folgefond glacier, 
near the Sorfjérd, a branch of the Hardanger, has had alterna- 
tion of advance and retreat, but that it advanced 40 metres 
between 1860 and 1878. This, no doubt, is an account of the 
very remarkable advance of the Buerbroe (broe is Norsk for 
glacier) near Odde, on the Sorfjérd. I visited the place in 1874, 
and the recent ploughing up of a considerable bit of the valley 
by the vast irresistible ice-plough was very striking, while the 
glacier itself was very beautiful. My object, however, is to 
repeat a stronge piece of folk-lore, which tends to show that in 
this particular spot, the advance of the glacier must have been 
long-continued, The legend was told me by Asbjorn Olseu, a 
very intelligent guide at Odde, who speaks good English. The 
tale was that long ago the Buer valley extended far into the 
mountains, and was full of farms and cultivation. It had also a 
q 
The Advance of Norwegian Glaciers | 
q 
: 
