292 
“the general consensus of the stars supports the result 
given.’ <A proof of that statement, a quantitative 
proof, will be found on pp. 42-44. I cannot 
encroach on your space to quote it here, but may 
briefly indicate its nature: P being the pole of the 
heavens and E the pole of the ecliptic, let P E C 
be a spherical triangle having E C 6°, P E 23° 27’, 
and P E C 174° 28’. Describe a small circle with C 
as centre and C Pas radius: then will W, where E C 
produced cuts the circumference of the circle, be that 
spot where is situated the so-called ‘“‘ Apex of Solar 
Motion.’’ The sides and angles given are not arbi- 
trary but depend upon the rate of precession and 
of the decrease in the obliquity at the commence- 
ment of this century, as is shown on page 44 of the 
pamphlet. ‘ 
This is a geometrical problem the significance of 
which your astronomical readers will readily appre- 
ciate. The facts it rests on are undeniable, and no 
alternative explanation to that suggested has hitherto 
been forthcoming. A. H. Barvey. 
Leppington House, 
Hertford. 
Mr. BaRLEy’s “ incautious reader ’’ would be quite 
correct in supposing that I had not only “ seen ”’ his 
pamphlet but read it carefully. It is not my practice 
to review works that I have not seen. I have, indeed, 
followed Draysonian publications with a melancholy 
interest from my youth up, and I cannot but regard 
them as an example of ingenuity misapplied. 
Mr. Barley in his letter does not touch on the points 
I made (1) that if the proper motions of stars were 
due to any shift of the earth’s:axis, all the stars in a 
given direction would move together, and there would 
be no relative shift among them. But in examining 
photographs of the regions round stars with sensible 
proper motions (say Capella) the P.M. star is clearly 
seen to be moving among the faint stars in the back- 
ground at practically the same rate as that given by 
the meridian observations. Indeed, Prof. Furuhjelm 
was enabled to detect a very distant companion to 
Capella by its sharing in its rapid motion relatively 
to the neighbouring stars. What is it then but “ wrest- 
ing ’’ evidence to denv the reality of Capella’s motion. 
(2) Mr. Barley denies the fact that the ecliptic is 
moving among the stars, and quotes Drayson as 
having tried to establish from the observations of Hip- 
parchus that such motion did not exist. This to me 
appears another flagrant example of wresting isolated 
observations. 
Hipparchus’s results were liable to errors of several 
minutes of arc, whereas modern results are accurate 
toa second or thereabouts. Hence we can get a better 
result from 50 years using modern observations, than 
from 2000 years using those of Hipparchus. The 
modern observations show unmistakably that the 
ecliptic is shifting. Of course it is impossible to give 
all the evidence for this in the course of a letter, but 
I have arranged a small number of observations in a 
way that will show an unbiassed reader that such is 
the case. 
The following table gives the North Polar Distance 
of the star 1 Geminorum as observed at Greenwich in 
different years, and also the North Polar Distance of 
the sun interpolated for the moment that its Right 
Ascension was the same as that of the star. It is to be 
noted that the N.P.D. of the star is referred to the 
mean equator of the year, that of the sun to the 
apparent equator affected by nutation; we can correct 
for this approximately by combining observations 
made about nine years apart when the nutation is 
opposite in direction and amount. 
NO. 2783, VOL. 111] 
NATURE 

[Marcu 3, 1923 
NORTH POLAR DISTANCE 
Year, Star. Sun. Star South Mean, 
1836 66° 44’ 7:71” 66° 32’ 39°05” ~ 11’ 28-66" 
1844 66 44 5°51 66 32 49°42 II 16:09 } 11’ 22:18” 
1855 66 44 1-70 66 32 39°92 Ir 21-78 
1876 66 43 55°85 66 32 39°54 Il 16°31 reer 
1885 66 43 54°99 66 33 1-23 10 53°76 5:08 
1902 66 43 51-90 66 33 2:57 TO 49°33 Lig age 
IgII 66 43 51°65 66 32 5140 II 0-25 5479 
It will be seen that in sixty-one years the sun’s path 
has moved southward relatively to the star 27-4”. The 
star itself is moving south 10-8” per century (Boss), 
so this has to be added to the southward movement 
of the ecliptic. It will be understood that I give these 
figures merely to demonstrate the reality of the move- 
ment of the ecliptic, not to determine its exact amount, 
for which further refinements would be necessary. 
I chose a star near the solstitial colure (1) because 
difference of N.P.D. practically agrees with difference 
of latitude, thus saving reduction; (2) because this is 
the neighbourhood where the ecliptic is moving south 
most rapidly. I reiterate my advice to Mr. Barley 
to study the whole of modern astronomy of position, 
instead of confining himself to a few selected portions, 
which he interprets in a way that further study would 
show to be untenable. 
THE WRITER OF THE NOTE. 

The Naming of Elements. 
SURELY the time has come to abandon the practice 
of attaching to elements fancy names arbitrarily 
selected by individuals. When names concerned 
nobody but a small clique in constant personal com- 
munication, and when they had nothing more im- 
portant to record about an element than the personality 
of its discoverer, there may have been something to 
say for the system. Nowadays neither condition is 
fulfilled. Thousands are interested who have no 
means of expressing their opinion : and there is some- 
thing definitely scientific to be said about elements. 
The new element was discovered as a consequence of 
a theory of the structure of the atom, and its dis- 
coverers should surely be glad to see a record left in 
the name that their discovery was no lucky fluke. 
Dr. Aston, who has discovered at least twice as 
many elements as anybody else in the history of 
science, has set a good example; he has waived his 
right of naming, undoubted under the old dispensa- 
tion. He has left them unnamed until a consensus 
of scientific opinion has established a scientific system 
of nomenclature. Will not others follow his lead ? 
Until its isotopic constitution is discovered, let us 
simply call the new element 72. 
NorMAN R. CAMPBELL. 

Sarsen Stones. 
REFERRING to the note on the discovery of the 
above near Maidstone, which appeared in NATURE 
of February 10, p. 195, may I direct attention to 
the fact that they occur in considerable numbers of 
large size, often in groups, near Faversham. The 
-otryoidal concretionary surface-feature is frequently 
present, but what appears to be of greater interest 
is that many of the blocks are perforated by long, 
tubular holes suggestive of the work of marine 
annelids anterior to the consolidation of the rock. 
The gravel pits in this district yield large masses of 
sarsen occasionally. One stone I found recently 
weighs more than 24 cwt., and can now be seen at the 
Twickenham Public Library. Full particulars ap- 
peared in the local press (Richmond and Twickenham 
Times, December 23, 1922). C. Carus-WILSON. 
Twickenham, February 19. 
‘ 
° weet weal 
a magne 
