ON SOME N.S.W. TA.N-SUBSTANCE3. 277 



Extract — 10*78 per cent. Colour light orange-brown; of moist 

 residue Vandyke brown. 



Tannic acid — 5*384 per cent. Non-tannin and impurities — 

 1*016 per cent., (determined on fair sections of inner and outer 

 bark, as usual). The flakes of the outer bark are so readily- 

 separable that the author considered it useful to make separate 

 determinations of the inner and outer barks. Outer bark — Yields 

 extract to water 3*08 per cent. Colour of dry powder, ground 

 coffee, which it much resembles ; colour of extract, sherry * of moist 

 residue, Vandyke brown. Tannic acid 1*524 per cent. Non- 

 tannin and impurities, *609 per cent. Inner bark — Extract to 

 water 31*38 per cent. Colour of dry powder reddish-buff; of 

 extract, orange-brown inclining to light ruby * of moist residue, 

 raw sienna inclining to brown. Tannic acid, 12*495 per cent. 

 Non-tannin and impurities, 1*117 per cent. From this it will be 

 seen that the inner bark is rich in tannic acid. These trees are 

 only used for fuel, for which they are excellent, and it does seem 

 a waste to allow so much tan-material to go unused. 



App's Induction Coil. 



In the Anniversary address delivered by the late Prof. Smith, 

 and published in the Journal of the Royal Society of N.S.W., 

 Vol. xviii., 1884, on page 14, line 13 it is stated — "This powerful 

 machine was ruined (as I understood) at the Paris Exhibition." 

 Mr. Apps in a note, which Prof C. Piazzi Smyth has communicated 

 to the Honorary Secretaries under the date 11th August, 1888, 

 says : — "I am sorry you have been misinformed from Australia 

 about Mr. Spottiswoode's (45" spark) coil. I employed an 

 Assistant at the Exhibition (in Paris) and he unscrewed one of 

 the connecting rods leading to the primary wire and thereby 

 stopped the primary current and no other damage was done. I 

 returned the coil afterwards to Mr. Spottiswoode, exhibiting the 

 full length of spark to him to show that the coil was uninjured." 



