882 Transactions of the American Institute. 



V. Manna. 

 Boussingault has given to the Paris Academy of Sciences an 

 account of his observations on a manna obtained from the leaves 

 taken from near the top of an old linden in the Yosges. Other 

 trees of the same kind in the vicinity yielded no manna. The 

 composition of this manna was found to be about fifty-five per cent 

 of cane sugar, twenty-six of glucose and twenty of dextrin. The 

 manna from Mount Sinai, examined by Ehrenberg and Bertholet, 

 had nearly the same composition, and was supposed to be an exuda- 

 tion caused by the puncture of an insect. 



Aktieioial Leatiiek. 



Dr. P. H. Van der Weyde exhibited a specimen of leather made 

 from waste leather scraps, which are treated in a way similar to the 

 manner in which glue is extracted, but not going far enough to change 

 the leather into gelatine. A small quantity of caustic soda and lime is 

 placed in a steam boiler with the scraps, and they are heated to about 

 a pressure of an atmosphere and a half. This makes a pulp, which 

 is treated like paper, made into sheets or into any required form. It 

 cannot stand wear and tear like common leather, but for insoles, and 

 for many other purposes, is just-as good. 



The President remarked that this would be inferior to leather 

 where the pores are useful to carry off the perspiration, and should 

 not be used where this is important. 



Dr. J. W. Richards — There is about the same relation between this 

 leather and the real skin leather, as there is between paper and linen 

 cloth. Paper is used extensively for insoles, and this is better and 

 cheaper to the wearer. It would make excellent packing. 



Dr. W. A. Wetherbee suggested its use as a substitute for papier- 

 mache. 



Dr. J. V. C. Smith said that it would certainly be better even for 

 the soles of boots and shoes than birch bark, which is sometimes put 

 into brogans intended for the southern market. 



Dr. J. W. Richards stated that in manufacturing towns leather 

 scraps are sometimes used for fuel. 



Dr. P. H. Van der "Weyde stated that nitrogen compounds are 

 made from them, as Prussian blue ; and that they are also used for 

 manure. 



Mr. Ball — They make a valuable charcoal. 



