a4 NATURE 
[Marcu 14, 1912 
around the ecliptic, being least pronounced probably 
when a minimum falls in an equinoctial month. A 
hasty comparison of Dr. Wolfer’s relative sun-spot 
numbers with the rainfall data of a few widely 
separated stations appears to hold out some encourage- 
ment for treating the data in this way. 
L8G. Scaurrz: 
Oficina Meteorolégica Argentina, Observatorio 
Magnético, Pilar, Cérdoba, January 16. 
Concentric Joints in Ice. 
In Nature for January 25 a correspondent directed 
attention to concentric joints and bulbs which he 
noticed in the thin ice-sheets which covered several 
small partially dried-up pools, and stated that he 
would like to have an explanation of their cause. 
I have seen circular ribs on the underside of ice- 
sheets on small pools which would appear to 
have been formed as shown by the accompanying 
diagram. 
When the pool was full of water, a thin sheet of 
ice formed between A and B. As the water sank into 
the ground an air space aa formed near the 
margins, the ice at the same time sagging. During 
the frost the further inward spread of the air space 
was arrested for a time by the freezing of the ring 
bb. Soon, however, in spite of the growth of the 
ring, the fall of the water-level allowed the air space 
aa suddenly to increase in size, and another ring was 
then formed inside the first, the process being re- 
peated several. times, until the water-level fell to E 
clear of the ice. From the water surface evaporation 
took place, and the vapour condensed on the underside 
of the ice-sheet, thickened it and made the ridges 
more pronounced and bulb-like. 
The number of rings and the thickness of the ice 
depend upon the keenness of the frost and the rate 
at which the water-level falls. 
A similar structure can be produced by perforations 
in thin ice-sheets partially supported by vegetation. 
‘The innermost ring is then the one first formed. 
The fact that lines of weakness are produced 
above each rib is interesting, but has escaped my 
notice. 
R. M. DEeELey. 
Inglewood, Longeroft Avenue, Harpenden. 
Remuneration of Public Analysts. 
On behalf of the Association of Chemical Techno- 
logists, I beg to enter a strong protest against the 
course of action that is being followed by the Lambeth 
and Wandsworth Borough Councils in regard to the 
filling of the appointments of public analyst for those 
boroughs which have become vacant by the death of 
Dr. John Muter. 
The terms of remuneration offered by both these 
borough councils are far below the lowest of the very 
inadequate rates of payment made to public analysts 
in London and throughout the country, and the 
acceptance of such appointments by a qualified scien- 
tific chemist on such terms would be degrading to 
the chemical profession and detrimental in the 
highest degree to the interests of the public. On the 
terms offered, it is absolutely impossible that the 
NO. 2211, VOL. 89] 
responsible duties attaching to such appointments can 
be efficiently performed. A public analyst has great 
personal responsibility, his position is one of consider- 
able anxiety, the value of his work is not generally 
understood, and the office he holds is widely disliked, 
for he is appointed under the provisions of Acts of 
Parliament which are extremely unpopular among 
certain sections of the community. It is therefore 
essential that he should be in a position of such in- 
dependence that he may not be liable to influence- or 
pressure from any persons whose interest it may be 
to prevent, so far as possible, the effective adminis- 
tration of the Acts. It must be remembered, too, 
that with the enormous increase in scientific adultera- 
tion, the work of a public analyst is to-day very 
different from the work required even ten vears ago, 
and it is therefore all the, more necessary that the 
general public for whose protection the Acts were 
passed should appreciate the advisability of prevent- 
ing the ever-increasing attempts of local authorities 
of a certain type to reduce the remuneration of the 
scientific officers concerned to a level rendering the 
satisfactory discharge of their duties impossible. 
J. WILBERFORCE GREEN (Secretary). 
30 Victoria Street, Westminster, London, S.W., 
March 6. 
The Storm of March 4. 
In Nature of March 7 reference is made to the 
storm of March 4, and figures are quoted giving the 
velocity of the wind recorded at several stations. It 
would appear that the storm attained a greater 
velocity here than at either of the stations named, and 
a few particulars of the record made by the Dines 
pressure-tube anemometer erected at Pendennis 
Castle, Falmouth, by the Meteorological Office, may 
be of interest. 
On the morning of March 4 a progressive mean 
velocity of from 20 to 50 miles an hour was recorded; 
at 6 p.m. it had increased to 65 miles per hour, and 
this velocity was maintained to midnight. The 
squalls were very violent; between 2 p.m. and mid- 
night a maximum velocity of 80 miles or more was 
registered more than twenty times, whilst the greatest 
squall attained a velocity of 98 miles at 6 p.m. This 
has been but once exceeded (or reached) since the 
anemometer was erected in 1902, viz. 103 miles at 
11.30 p.m. of March 14, 1905. 
Epwarp Kirro (Superintendent). 
The Observatory, Falmouth, March 11. 
Chserved Fall of an Aérolite near St. Albans. 
DurinGc a heavy thunderstorm which ensued on 
Monday, March 4, between 2.30 p.m. and 4.15 p.m., 
an aérolite was observed to fall at Colney Heath, near 
St. Albans. The observer, who has placed the speci- 
men in my hands for examination, stated that the 
stone fell within a few feet from where he was stand- 
ing, and that it entered the ground for a distance of 
about 3 ft. Its fall was accompanied by an unusually 
heavy clap of thunder. The example weighs 5 Ib. 
143 oz., and measures 6% in. x52 in. at its greatest 
length and breadth respectively. The mass is irregu- 
larly ovate on the one side, and broken in outline on 
the other. The actual surface throughout is fairly 
deeply pitted, and under magnification exhibits the 
usual chondritic structure of the crystalline matter, 
with interspersed particles of what appears to be 
nickeliferous iron. 
G. E. BULLEN. 
Hertfordshire Museum, St. Albans. 
