Purkinje, Dr. E. 



Weiswasser, September 19$ 1879 



Dear Sir: 



I am sending the cards with the stations and have some 10, which have grown since 

 my last letter, entered with red color. I will soon follow up sending the February 

 issue, which is now in print. I would like to know if also in America the rain and 

 snow falls simultaneously, are spread over large land areas . In Russia this is the 

 case. This time I am writing regarding a particular matter and ask therefore if you 

 will please make inquiries and send me a special answer. In my report on forestry 

 from N. A. I read that in America Rhus typhina and Rhus glabra are used for tanning, 

 that is with the addition that only the Rhus from the southern states have enough 

 tanning material; in the meantime I would like to have tests made if that grown in 

 Bohemia is not suitable for it, because Rhus typhina grows so luxuriantly here, is 

 much easier to cultivate than the oak and is tolerant of all soils, but especially 

 thrives well in the poorest; this is less the case with Rhus glabra , which neither 

 gets high nor sends out so many runners. But nevertheless it is far stronger than 

 Rhus Cotinus , that from Hungary and South- Tyrol in various forms (wood-cuts, young 

 branches, dry leaves) as tanning medium, but especially as excellent coloring medium 

 (black with sulphate of iron) comes into trade here. Now I would like to know: 



1) In which form is Rhus typhina used in America, in the bark, the wood, the branches, 

 the leaves, fruit. 



2) At what time of the year the used parts are taken, if in Spring, Autumn or Winter. 



3) If there are actually noteworthy differences in the material from the various 

 States. 



What the manipulation is when tanning, if the commodity will be ground and 



how it is extracted, how much approximately one needs on an ox hide and how the 



leather tanned with it compares with that tanned with tanbark. The Boheraian 



tanners in the Country raostly tan with spruce (pine) bark and the oak bark of our 



coppices goes only to the tanneries of the large cities, but especially to 



Prussia. 



Years ago I corresponded with a Berlin tanning-master about the quality of the bark 

 according to the origin and learned that the southerly ones certainly have more 

 tanning material, but particular ly that of Quercus Hex . Still stronger the oak apple 

 work and the calyxes of Quercus Valon«a, a variety belonging to Cercis, which I 

 tried unsuccessfully until now to achieve from acorns, which are found under the 

 calyxes of the almonds. 

 5) Are oak bark and calyxes used in America for tanning, and how do the groups 

 of alDae » Prinos , Erythrobalanos , Phellos conduct themselves in this regard. 



