24 



APPENDIX A. 



IMPORTANT TANNERS' PLANTS, WHICH COULD ADVANTAGEOUSLY BE 

 REARED IN THE CLIME OF VICTORIA. 



The Sumach plant. Rhus coriaria, a shrub or small tree of South Europe, North Africa, 

 South- Western Asia, and also of Madeira and the Canary Islands, where it naturally grows 

 on arid hills. The twigs and leaves, merely reduced to powder, constitute the sumach of 

 commerce. It yields up to 30 per cent, tannin (gallo-tannic acid), and is a needful article 

 for the production of the best Corduan or Maroquin leather. The cultivation of the 

 sumach-bush is in no way beset with difficulties, as it will live even on poor soil. Under 

 favorable circumstances as much as a ton of sumach may be obtained from one acre. 

 Several North American species of Rhus (viz. R. glabra, R. typhina, R. copallina) produce 

 also a good tanner's sumach, but it is necessary to collect the leaves in the spring, if 

 white leather is to be obtained ; the percentage of tannin increasing during summer, but 

 the foliage then imparting a tinge to the leather. All these sumachs, with several others 

 (from various parts of the globe), some of which have not yet fully been tested, were many 

 years ago introduced already into the Botanic Garden of Melbourne, as well as the 

 following species. 



The Scotino plant. Rhus Cotinus, a bush occurring in the countries around the Medi- 

 terranean Sea, thence extending to Southern Russia. The ground leaves and young 

 branches constitute the commercial article. Both sumach and scotino shrubs become as 

 early productive as the vine, while their products, unlike the wine, are ready for the 

 market almost immediately after the harvest. 



The Valonia Oak. Quercus ^Egilops and Q. macrolepis, two oaks of the regions at the 

 Mediterranean Sea. The cups of the acorns constitute the Valonia. The same oaks 

 furnish in their young acorns the Camata, and in the still younger fruits the Camatina. 

 The Valonia oaks can here be raised as easily as the English oak, though they are not of 

 quite the same celerity of growth. Both Valonia and cork oaks might with advantage be 

 planted along our railway lines, and for shading roads, and they should also engage atten- 

 tion extensively in our forest culture. Valonia imparts a rich bloom to leather. 



The Divi-Divi plant. Ca3salpinia coriaria, a shrub or small tree, native of the moist 

 sea-shores of Central America. Very likely this Csesalpinia, like several of its congeners, 

 would live in our extra-tropical latitudes. The husks of the pods form the Divi-Divi, 

 one of the most powerful and quickly acting tanner's material. The extract of Divi-Divi 

 produces a bloom on leather. 



The Huntingdon Willow (Salix alba) furnishes tanner's bark for glove leather of particular 

 fragrance. The Bedford willow (a form of Salix fragilis) is likewise rich in the tannin of 

 its bark. Splendid glove leather is also produced in Scandinavia from elm bark. 



The Birch (Betula alba) furnishes in its bark material for the Russian Juchten leather. 



The West Australian Tanner's Wattle (Acacia saligna), which proves there so highly valu- 

 able, could be with the same ease disseminated here as our own wattle-acacias. 



Many other plants might be mentioned as yielding tan-substances, but the above are 

 the principal extra Australian plants which at our present yet early stage of colonization 

 could be recommended to supplement our almost incomparable acacia barks for particular 

 products of tanneries. The work of the writer on " Select Plants " can be consulted also 

 in reference to a multitude of other tanners' plants, fit to be reared in our clime. On nume- 

 rous important questions concerning the action of tan-plants, Dr. Morfit's large work on 

 tanning and currying leather may be referred to. 



MEANS OF ASCERTAINING STRENGTH. 



Exhaust the bark with boiling water, filter, add a solution of chromalum so long as a 

 precipitate is deposited, let stand for a few hours, collect the precipitate on a filter ; wash 

 out, dry at 212 F., and weigh ; then incinerate the dry precipitate, and weigh again the 

 remaining oxyd of chromium. The first weight, minus the latter one, gives the amount of 

 tannic acid. A less accurate method is to ascertain by a tan-meter the specific gravity of 

 the tan-liquid. Closely approximate results are also obtainable by using a standard solu- 

 tion of isinglass or, better still, quinin, the strength of which to precipitate an ascertained 

 quantity of tannic acid being known ; the measurement can be effected in graduated test 

 tubes. 



