1908-9.] ON THE ORIGIN OF THE CANADIAN APATITES. 507 
of sodium carbonate, and subjected the whole to a constant temperature 
of 160 degrees for six days. ‘The results were as follows: 
I II 
before after before after 
EE QORS ttn const eerie 41.97 41.78 41.01 40.90 
Barone a chep ton eee ake 3.63 3.60 0.85 0.80 
(Close amen Mens 0.03 tr 5.31 4.60 
CO 2h he ara ale cmamhlc ste Ol) SETGa hei we 0.48 
CAjOee TRB secs 54.65 54.60 53-44 53-45 
IMO reer echt eh ara Meas AAI Pee akecks 0.17 0.20 
Be Onccedecewo ae tes 0.48 0.36 0.20 0.05 
ey Oey heya! nal cle a aN Oe 0.53 0.67 
Sy OL agodnee easel 0.80 0.72 0.14 O.II 
100.56 LOW sz 101.65 IOI .26 
I II 
Esreplaced! byiCl iso. t. sare aie welece'e 0.00 0.85 0.80 
Bireplaced by CC aaa gestae 0.00 2.84 2.46 
0.41 
PRO tales Gee ke et tal Oat aap 3.65 3.69 3.67 
IN OPI EY eran tsk sors sievorace eras Bea 3.66 3.65 
These analyses not only agree with Carnot’s theory, but in the second 
specimen, a typical chlorapatite one-seventh of the chlorine had been 
replaced by carbon dioxide. 
35. It is evident then that the researches of Carnot throw much 
light upon the interesting question of the origin of the apatites. He 
has shown in the first place that decaying organic matter has the property 
of absorbing phosphoric acid from solutions, even when present in almost 
infinitesimal proportions. He has shown further that calcium phosphate 
in turn absorbs fluorine tending towards the stability of the apatite-mole- 
cule, and also that this has actually occurred in the case of fossil bones. 
Further experiments showed that in the apatite molecule, the fluorine 
is frequently partially replaced by chlorine and carbon dioxide, and that 
this state of affairs may be artificially reproduced in the laboratory. 
36. In short, it may be said when we compare the various phosphates 
with apatite, that they differ from it in chemical composition just in pro- 
portion as their date of origin is distant from the primeval time when 
the apatite-bearing rocks were laid down. Here and there, it is true, 
we find among the masses of rock phosphate, crystals of true apatite 76 
but they are as minute as they are rare, and are of interest as illus- 
trating a petto, the gradual change in composition towards a more and 
more stable molecule. 
26 Penrose, op. cit. p. 47 and 89, also C, R. 
