200 
PROCEEDINGS OF THE NATURAL [APRIL, ’89- 
them to cohere. The native double fluoride (cryolite) can 
be obtained much cheaper than the double chloride. 
From the Government reports of mining and mineral 
statistics the amount of cryolite imported into the United 
States is from 5000 to 8000 tons per year at a cost of 
about $15.00 per ton. Thiscost, the Pennsylvania Salt Co. 
(who control the cryolite business in this country), have 
told me is incorrect and too low. 
They sell what they call pure cryolite at $125 per ton, 
01 cen ts per pound. This would make the cost of an 
amount sufficient for one pound ol A1 65 cents, supposing 
ie yield of A1 is 10 per cent, of the salt (theoretically 
y 3 percent.) This so-called pure cryolite from the 
ennsylvania Salt Co. contains, I find, 2 percent, of silica 
and 1 per cent, of Fe. I am confident that the artificial 
uonde can be prepared at half the cost and of much 
g eater purity than the natural cryolite. 
900 a meltl ”f point of the double chloride is less than 
’ T hilC tHat ° f PWe A1 is 700 degrees C.and 
fluid a n aT y 1000 C ’ SO the Al'is perfectly 
the same t rea r° hereS When reduced ^om cryolite. At 
voSe r e 41 T mperatUre is not sufficiently high to 
vanta? a ! he ^ C ?’° lite or <**er fluoride has ihe disad- 
to fluxlhe C °“ pa T ed w *h the double chloride of tending 
n the selet" ^ ^ neater care is necessary 
ings and th" f ° r C ™ cib ^ crucible lin- 
circumstances wm permh The ^ ^ ^ l0W “ ° thCr 
transfer resign • . lcie ls difference in the 
of Chlorides of the alkabesor ofthe alkal ^ ‘ T ‘^Ts 
diffusion^nd'reunio^of the ° rC S ° 1Uti ° n ° f ^ ^ ^ 
sis of the double fluoride than of the deCtr ° ly ' 
repeatedly passed current of 60 r T I have 
Pare melted cryolite for several h ° amperCS thr ° UgH 
hours without obtaining 
