194 BULLETIN OF THE BUSSEY INSTITUTION. 
page 207. For example, Wolff’s table gives the proportion of lime in 
birch-wood ashes as 607%. But as appears from the table on page 207, 
ashes from birch wood contain on the average about 28% of carbonic acid, 
sand, and charcoal, and species Nate about 72% of ash that is free from 
those substances. But 7 qis of 60 = 43, or thereabouts ; and this number 
probably represents very nearly the average amount of iide that. actually 
exists in sifted birch ashes. 
METHODS oF ANALYSIS. 
Care was taken in eyery instance to draw an average sample of the 
ashes from the bin or barrel that contained them. The rough sample 
thus taken was sifted through a sieve carrying twelve meshes to the 
linear inch,* and the fine powder, thoroughly mixed, was kept in a tight 
bottle. All the samples examined were completely dry in the ordinary 
acceptation of the term, but none of them were subjected to any pro- 
cess of drying in the laboratory, excepting the samples to be mentioned 
directly, in which the amount of hygroscopic moisture was estimated. 
The portions weighed out for analysis were purposely taken as nearly 
as possible in their natural condition. Except for the sifting, which 
was absolutely necessary to ensure a certain degree of uniformity in 
each sample, the ashes analyzed differed in no respect from those of 
every-day life. The amount of hygroscopic moisture contained in most 
of the samples was very small. Thus a weighed portion of No. III. 
* Only a very small proportion of the original ashes was left upon the sieve 
in most instances. Even the mixed ashes from the soapboiler gave a compara- 
tively small volume of ‘coarse material. The siftings were, however, rather 
heavy in that case, because of the presence of nails and particles of gravel. 
Besides charcoal and bits of half-burnt wood, the sieve removed from the soap- 
boiler’s ashes many iron nails, fragments of glass, and pieces of bone, with 
here and there a broken tobacco-pipe, and a bit of crockery ware, brick, or 
stone. 
In order to gain some idea of the amount of matter woparaeaa by the sieve, 
a number of two-pound samples, taken from different parts of one of the barrels 
of ashes obtained from the Southbridge soapboiler, were carefully sifted, and 
the weights of the residues left in each instance were noted. The results were 
as follows: Eight separate portions, of 1000 grammes each, taken from the upper 
third of the barrel, gave, respectively, grammes of coarse material, 125; 148; 
143; 155; 149; 158; 190, and 170. (Mean of the eight trials: 154 grammes, 
or 15.4%.) 
Five portions, of 1000 grammes each, taken from the middle part of the bar- 
rel, gave grammes of coarse material, 187; 195; 168; 188, and 166. (Mean of 
the five trials : 181 grammes, or 18.1%.) . 
Five portions, of 1000 grammes each, taken from the lower third of the bar- 
rel, gave grammes of coarse material, 201; 150; 180; 157, and 160. (Mean of 
the five trials: 169 grammes, or 16.9%.) 
