Marcu 17, 1904] 
IMA TORE 
475 
abundance of sulphates, and since radium sulphate is one | 
of the most insoluble salts known, there could not be more 
than the merest traces present. The sulphate of barium 
is very much less soluble than that of strontium, and pre- 
sumably the sulphate of radium is much less soluble still. 
Barium sulphate requires half a million times its weight | 
of water to dissolve it; radium sulphate perhaps several | 
hundred million times its own weight. | 
About ro litres of the Bath water were evaporated to dry- | 
ness. The resulting saline residue was sealed up in a hard 
glass tube, and left for about a fortnight to generate a 
stock of emanation. On heating, a distinct emanation was 
obtained, giving several times the rate of leak that air did. 
A deposit, similar to that from the Bath water, but black | 
in colour, can be collected from the source of the hot springs 
of Buxton. It has been analysed by Dr. J. C. Thresh | 
(Proc. Chem. Soc., January 17, 1882), and I am indebted | 
to his kindness for a specimen of it. This deposit was found 
to contain radium also, the proportion present being not 
very different from what was found in the case of some of 
the Bath deposits. 
The following table gives the quantitative data for these 
emanations from these deposits. The rates of leak are on 
the same scale as those in the preceding table. 
ij . i] 
bike % nyOBs 
2g jxazivie [S283 
Sq j@do sete ssa | 
4 BE (eS GeO G Eel Aiea 
Material Be jOvPZcis%*og soec_ 
Sh loorsjoge aos eos 
= Seca fer feogrs 
fe [SestiSesMiagesis 
S MBS Bas NaS oe | 
King's Spring, Bath— | 
Deposit from inside of well . 10 250 | 2,500 | 3°60 
a, fi AST To Boeke 3 12 782) 650 | _— 
Saline residue from water . . . 18 12°4 69 =— 
Old Royal Spring, Bath— 
Deposit from channel near well . 10 6375] 635 | _ 
35 yy , bottomof tank. . 15 60 | 400 _ 
Hard deposit from sides of tank . | 25 43. | 173 3°58 
Buxton deposit . 26 BEONE exes 7ONN las ia Sr 
| 
It will be seen that the richest of the deposits is some | 
thirty-six times more active than the salt obtained by | 
evaporating the water. 
Although the agreement in the rate of decay of the 
emanation seemed sufficient to prove 
that the activity was really due to 
radium, yet it was thought desirable to 
show that the chemical properties of 
the active constituent were in agree- 
ment with this conclusion. Two hun- 
dred grammes of the richest deposit 
were treated with dilute sulphuric acid. 
The activity was all in the insoluble 
residue, which was dirty white in 
colour, and amounted to about half 
the entire quantity of deposit. The 
residue was boiled with strong sodium 
carbonate solution. This was washed 
away, and the mass extracted with 
hydrochloric acid. The hydrochloric 
acid solution gave a slight precipitate 
with sulphuric acid. This precipitate 
was collected, and found to be strongly 
active, so that there is every reason 
to conclude that the activity of the de- 
posit is due to the presence of radium. 
The presence of radium in the Bath 
water and deposits is of special interest 
because of the occurrence of helium in 
the gas which rises with the spring 
(Rayleigh, Roy. Soc. Proc., vol. Ix. p. 
56). There can be little doubt that the 
helium owes its origin to the same 
store of radium that supplies the water. 
It is interesting to estimate the 
quantity of radium annually delivered 
by the spring. Part of this is in the 
deposit, part in the water. But the annual yield of de- 
posit does not exceed a few hundredweight at the most; 
and although it is much richer in radium than the dis- 
solved salt, the quantity of the latter is so enormously 
NO. 1794, VOL. 69] 
greater that the deposit may be neglected. According to 
the estimate of Sir A. C. Ramsay, the late director of the 
Geological Survey, the salt annually delivered by the spring 
would be equivalent in volume to a column 9g feet in diameter 
and 140 feet high. Taking the density to be twice that of 
water, this would weigh about 5co,o00 kilogrammes. 
Now the saline residue gives about 1/150oth part of the 
quantity of emanation that samarskite gives. Let us assume 
that the latter contains one-millionth part of radium, which 
is, I think, an outside estimate. At that rate, the annual 
delivery of radium by the spring amounts to about one-third 
gramme. The volume of gas which the spring delivered 
is about 100 cubic feet. per day (Williamson, British 
Association Reports, 1865, p. 380). About 1/1o0oth part of 
this is helium, so that about 3 litres of helium are given off 
daily, or about 1voo litres per annum. ‘The proportion of 
helium to radium thus indicated is of the same order as in 
the radio-aclive minerals, though somewhat larger. This 
is in accordance with the view that the spring draws its 
supplies from the disintegration of such minerals. 
In obtaining the various materials from the Bath springs, 
I have had the great advantage of Mr. Sydenham’s help. 
His knowledge of everything connected with the springs 
has been of great assistance. 
In addition to the Bath and Buxton waters I have ex- 
amined several others. 
A sample of the Cheltenham saline water, and also a 
deposit left in the pipes, was kindly sent me by Mr. G. 
Ballinger. But no emanation could be obtained, either 
from the dissolved salts or from the deposit. 
The boiler crust from a domestic hot water pipe, Terling, 
Essex, was examined, but the result was again negative. 
THE MINING OF NON-METALLIC 
MINERALS.? 
THE four Cantor lectures delivered before the Society 
of Arts last year by Mr. Brough, and now published 
as a pamphlet, form a fitting sequel to the course which 
he gave in 1900 upon metalliferous deposits. The title 
““non-metallic minerals ’’ must be taken in the popular and 
not in the strictly scientific sense, and is intended to include 
all the useful minerals which are not employed as sources 
of the common metals. Mr. Brough classifies these minerals 
Fig. 1.—Magnesite Quarry, Salem, India. 
into four groups, viz. coal and bitumens, salts, stone and 
precious stones. 
2 By Mr. Bennett H. Brough. Pp. 48 and rs figures. (/ournad of the 
Society of Arts, December 25, 1903, January 1, 8, 15, 1904.) 
