Oct. 22, 1885 | 
NATURE 
Bo7 
they were in some sort original. You mention as a kind of 
palliative that, although my priority is not distinctly admitted, 
my name is mentioned in a prominent manner. 
Personally I consider this a very small affair. Long experi- 
ence of having my name mentioned in a similar manner, or 
mixed up with the names of others, or altogether omitted in 
connection with certain coal-dust matters in which I have un- 
deniable priority, has hardened me ; and I confess that this part 
of your letter gave me noconcern. But although I could afford 
to pass it over in this way as far as I am myself concerned, I 
cannot adopt the same course when the interests of some of the 
members of the Royal Commission on Accidents in Mines are 
also at stake. 
I must therefore ask you to give me a token of your good 
faith by restraining your friends from publishing anything further 
until the English Royal Commissioners shall have seen fit to 
make known the results obtained here. At the same time also 
I would suggest it asa simple matter of duty on your part to 
take immediate steps to let it be known to those before whom 
your friends’ communications have appeared that the credit, if 
any, of the original investigations in this case rests with Sir 
Frederick Abel and Mr. W. Thomas Lewis quite as much as 
with me. Believe me yours very faithfully, 
W. GALLOWAY 
Herr Bergrath Kreischer, Professor der Bergbaukunde, 
Freiberg, Sachsen 
The Resting Position of Oysters 
In books on Conchology, such as Woodward’s ‘‘ Manual of 
the Mollusca” and Jeffrey’s ‘‘ British Conchology,” it is stated 
that the oyster rests in the natural state on its left valve, which 
is the larger and more convex. In this respect it is pointed out 
the oyster differs from the animals belonging to the genera 
Pecten and Anomia, which rest on the right valve, the Anomias 
being firmly attached by muscle with the flat right valve applied 
closely to the surface of attachment. In his lecture on oysters 
at the Royal Institution, which was published in Nos. 1 and 2 
of the Znglish Jlustrated Magazine, Prof. Huxley also states 
that oysters rest on the left or convex valve, the flat right valve 
acting as a kind of operculum. Examination of oysters from 
the Firth of Forth has convinced me that this statement is 
erroneous. I do not know on what evidence the current belief 
of conchologists is founded. The evidence which appears to 
me conclusive is that the right flat valve is always quite 
clean, while the convex valve is covered with worm tubes, 
Styela grossularia, and Hydroids. The latter are in this con- 
nection the most important ; it would be impossible for specimens 
of Sertularia and Thuiaria 4 or 5 inches long to grow, as I have 
found them on almost every oyster, in the central part of the 
left valve, if that valve were the lower in position. On examin- 
ing Pectens I found that they resembled the oyster in the con- 
trast between the surfaces of the two valves, the upper convex 
one being covered with Balanus and other fixed animals, the 
lower being almost clean. It is generally stated that the Pecten 
lies on its right valve ; if this statement rests on the evidence 
afforded by the condition of the surface of the valves the same 
criterion applied to the oyster leads to the same conclusion, that 
the right valve is the lower. I have never seen a young oyster 
in the attached condition: Huxley states that it is the left valve 
which is fixed ; in papers on the embryology of the oyster I have 
not yet been able to find any definite information on the point. 
Whether it is the right or left valve that becomes attached when 
the larva assumes the sessile condition I cannot therefore say of 
my own knowledge, but with regard to the adult oyster it seems 
to me certain that the current belief is caused by the repetition 
ofan error. My attention was first called to this point by my 
assistant, Mr. John Walker, who tells me that the opinion of | 
the fishermen at Newhaven is divided on the point, some saying 
that the convex valve, others that the flat valve, is the lower. 
J. T. CUNNINGHAM 
Scottish Marine Station, Granton, October 14 
Two Generalisations 
Two generalisations seem to have been staring us in the face 
for some time, and yet I have seen no one give them a look of 
recognition ; they may be phantasms, but they seem solid 
enough :— 
(1) That the number of elements is infinite ; the most readily- 
formed types of ethereal vortices being the commonest, but our 
knowledge of them being only limited by the scarceness of the 
more complex forms, and not by any limit to the infinite varie- 
ties of complexity that may exist. hei relative commonness 
being analogous to the relative sizes of the bodies of the solar 
system ; a few large, and always recognisable, and a greater 
number of examples as we descend in size to mere meteors. We 
already see that there are far more rare elements known than 
common ones. 
(2) That the reduction of an electric current to heat in an 
imperfect conductor is solely due to the independent heat- 
motions of the molecules, which check and divert more and 
more of the current as their motions are larger ; if there were 
no pre-existing heat-motions there would be nothing to resist a 
complete transmission of the current motion, and hence there 
would be no limit to conduction at the zero of temperature ex- 
cept the cohesion of the material. 
Bromley, Kent W. M. FLINDERS PETRIE 
Meteors 
ON the morning of October 13, at 2h. 26m., I saw a fine 
meteor giving a bright flash at the end point and leaving a streak 
for about 12 seconds. It shot from the Lynx towards the 
pointers in Ursa Major, and while carefully fixing its direction 
relatively to the stars near, another conspicuous meteor, about 
as bright as Jupiter, crossed the lingering streak in a path but 
slightly inclined to it and of nearly similar length. I have never 
before observed two large meteors almost simultaneous and with 
paths so nearly identical. 
I subjoin the observed paths of these meteors, also of five 
other bolides recently noted here during the progress of my 
habitual watches for shooting stars :— 
Path 
1885 G.M.T. Mag. From To Length Radiant 
h. m. ° ° ° 0 °. o ° 
Sept.9 15 48 zy 149) 82) 152) 64) (18) 335-70 
o> GG a 1 37 + 64 2644+ 7 0k Jot 4 
Oct 7 1051 Y 51s+22 71k +24 18 31+18 
» 8 15 9 & 155 +53 162k+465 .8 42+55 
i) 12) 14, 26 ? 119 +51 151 +604 20 88 +18 
oe 22) 1 4).26 4 119s+50 143 +604 164 103+33 
3) Os 1 S35 Y% 213 +47$ 226 +41 Ir 143+49 
The radiant points are derived in each case by combination with 
many other meteors registered on about the same nights. I 
have seen 357 meteors since early in September, and those 
selected in the above table comprise a!l the brighter specimens 
estimated to equal Jupiter. W. F. DENNING 
Bristol, October 17 
Statigrams 
THE increasing use of graphic representations of statistics by 
means of lines, areas, &c., seems to render it convenient to 
have some word which would specially designate diagrams 
exhibiting the progress and tendencies of the numerous tables of 
figures which do not pretend to strict scientific accuracy. The 
word azagram is used in most elastic senses and by all sorts and 
conditions of men. 
May I suggest the word s/etigraph as a definite and con- 
venient one for adoption? This might be sometimes shortened 
to graph ; whereas statigram, if preferred, would not admit of 
this abbreviation. Most, if not all, graphic results of statists, 
economists, anthropologists, &c., might thus be termed graphs, 
whilst mathematicians and the experimental men of science would 
be left with the use of their own words, such as curves, 2xd2cator 
diagrams, &c. Each class would possess its own degree and 
limits of accuracy: mathematical precision and the doctrine of 
energy would apply to the latter, but gzafhs would be under- 
stood to involve human elements with intricate factors whose 
recognition or relationships the statistics are intended to elucidate 
and compare rather than to define and measure. 
12, Merton St., Oxford J. F. HEYES 
THE GEOLOGICAL SURVEY OF BELGIUM 
|2 BQeeveit no country of Europe has had its geology 
more attentively studied and mapped than Belgium. 
From the early labours of the veteran and pioneer 
