336 Canadian Record of Science. 
proportion remains as an unoxidisable or incombustible 
residue—the ash. 
The relative proportions of combustible and ash con- 
stituents, are subject to wide variations, not only as 
between different species, but even in the same species 
under different conditions of growth and of food supply, 
An illustration of this law may serve to make our state- 
ment more clear. In the Tenth Census Report of the United 
States for 1880, Prof. Sargent gives the ash percentages for 
somewhat more than four hundred species of woods. Select- 
ing from these the extremes, we find the following :— 
Org. Mat Ash. 
WOE GENE oodG00 Bo0000 DOOD 00b6 coUOKe 90.72 9.28 
Pseudotsuga Douglassii.. HAD CIRCE HOES 99.98 0.02 
Again, between these and herbaceous plants, in which 
relatively less mineral matter is observed, the difference 
would be more striking, Another illustration of the law 
stated, is afforded by the results obtained by Arendt in his 
analysis of 1000 oat plants selected at different periods of 
growth, with intervals of about twelve days. His results 
were as follows :— 
June 18.) June 30. | July 10. | July 21. | July 31. 
3 leaves Heading. Blossom- Ripening.| Ripe. 
open. ing. 
Sra tae ew 1.06 2.71 2.68 4.83 5.84 
PROM con, 3.27 5.99 | 10.32 | 12.90 | 14.93 
Ke Ofori, cae 17.05 | 31.11 | 40.20 | 44.33 | 43.76 
CRORE ee ee 4.48 8.50 | 11.60 | 14.94 | 14.71 
Merona. wks: 1.53 2.71 3.71 5.42 6.45 
IMS, Omodauna wees 0-20 0.46 0.61 0.83 0.58 
SOM else wes. 6.39 | 15.82 | 25.45 | 34.66 | 36.32 
NaNO sees 0.86 1.28 1.47 1.12 0.87 
Clic cea ais ee 2.28 3.62 5.32 5.96 5.78 
Total grammes ....37.12 72.20 101.36 124.54 128.04 
Gain for each period........ 35 .08 29.16 23.18 3-50 
