BULLETIN OF THE BUSSEY INSTITUTION. 197 
In sample No. III. the second analyst, Mr. Leman, estimated the 
phosphoric acid by precipitating with molybdate of ammonia,* from a 
nitric acid solution of the ashes, after silica, sand, and charcoal had been 
eliminated. Ignorant, as before, of the result (1.62%) previously obtained, 
he found 1.56% of phosphoric acid. This evidence was conclusive as to 
the general accuracy of the uranium process. Still it was not impossi- 
ble that a part of the phosphoric acid in the ashes might be in the condi- 
tion of some other modification than the ordinary tribasic variety, tm 
which event a part of it would not be precipitated by the reagents em- 
ployed in the processes that have been described thus far. Several quali- 
tative trials, made with different samples of ashes, and by various 
processes to test this idea, gave no reactions other than those of the tri- 
basic phosphate. A quantitative estimation of the phosphoric acid in 
sample No. III. was made also after the material had been subjected to 
treatment which should convert any pyro- or meta-phosphate the ashes 
might contain into the ordinary phosphate. The silica, sand, and charcoal 
having been separated in the manner above described, the dry residue 
obtained on evaporating the filtrate was fused with a mixture of carbonate 
of soda and chlorate of potash, + and the phosphoric acid, estimated as 
usual by means of a standard uranium solution, after separation and 
collection of the phosphate of iron. There was found 1.40% of phos- 
phoric acid, or rather less than before. 
Finally, samples Nos. V. and XII., in which exceptionally large amounts 
of phosphoric acid had been indicated by the usual uranium process, were 
precipitated anew by means of molybdate of ammonia, after the silica, 
sand, and charcoal had been separated, and the dried residue of the filtrate 
therefrom had been fused with carbonate of soda and chlorate of potash. 
There was found in No. V. 1.559% of phosphoric acid; 7.e., decidedly less 
than by the uranium process, and in No, XII. 4.580 or almost one per 
cent more than had been indicated by the uranium method. As regards 
No. XI. the discrepancy is doubtless due to the circumstance that this 
particular sample of ashes was so little homogeneous that the portions of 
material taken for analysis by the different operators could hardly have 
been of like composition. In point of fact the pitch-pine ashes were 
highly charged with silicious sand in grains of the most diverse sizes. 
The peculiarly coarse, rough bark of the pitch-pine is well adapted to 
catch and hold considerable quantities of sand and earth, even when the 
trees are standing. ‘The large amount of phosphoric acid found in No. 
XII. may be due either to the large proportion of bark which belongs 
to pitch-pine wood, and which is probably richer in phosphoric acid than 
the wood, or possibly to the burning of pine cones in conjunction with 
the wood. Perhaps the peculiar manner in which the wood in question 
* After Fresenius’s “ Quantitative Analysis,’ New York edition of 1871, 
p. 271. 
1 After Gilbert, Fresenius’s ‘‘ Zeitschrift ftir analytische Chemie,” 1873, 12.3. 
