BULLETIN OF THE BUSSEY INSTITUTION. yA 
Percentage of : — 
Phosphoric acid in the ash . . 2.37 8.08* 2.06% 2.50 
Potash * Ta are 1 7. 9.43 6.07 8.02 
Lime fpereat ee LB — —_  — 
Silica and sand __s,, Pee 2.08 —— — — 
Ash in the anhydrous materials 1.89 1.57 1.97 1.81 
Spent tans: IL. Iy. MRO a tepane 
Water, expelled at 105°to110° 15.06 13.27 13.66 14.00 
CN ae 1:77 1.59 2.03 1.80 
he tg 1s i a rr 0.0316 0.0398 0.0383 0.0366 
(os). | ee ae 0.0564 0.0902 0.1049 0.0838 
ieee. « ... - 0.099—0.139 0:165°° 0.200 0.1613} 
Percentage of: — 
Phosphoric acid in the ash* . 1.79 2.51 1.89 2.06 
Potash * i eit 3.19 5.68 6.18 4.68 
Ash in the anhydrous materials 2.08 1.83 2.35 2.09 
Spent SuMACH AND Loawoop. 
VII. A large sample of spent sumach from Nath. R. Leman, Jr., 
morocco manufacturer of Chelsea, Mass. It was brought to the labo- 
ratory in the actual tub or vat in which the powdered material ¢ had 
been percolated, the tub and contents weighing more than a hundred 
pounds. ‘The sample was still very wet, and it gave a decided acid 
reaction to test paper. It had been leached with water acidulated 
with sulphuric acid. Dried at 100°, a quantity of this wet material 
gave off 69.89% of water. 
VIII. Finely ground, fresh logwood, obtained from the Boston Dye- 
wood and Chemical Co. 
IX. Finely ground, spent logwood, obtained as above. 
The following results were obtained on analyzing these substances, — 
* The items marked with an asterisk have been calculated from the amounts 
of phosphoric acid and potash found in the nitric acid solutions of the tans, to 
be described hereafter, under “ Methods of Analysis,” and from the weights of 
total ash obtained on burning the tans. 
+ Steckhardt, in his Chemische Ackersmann, 1855, 1. p. 192, § 87, reports 
a quarter of one per cent of nitrogen in spent tan (perhaps from oak bark), ob- 
tained at Tharand in Saxony. 
t Leaves and young branches of Rhus Coriaria. 
