H. Goadby on making wet Preparations of Animal Substances. 23 
geons, with which I had the most complete success. As made 
or general use the marine glue consists of different degrees of 
hardness, distinguished by numbers, from one, downwards ; the 
particular composition made for me agreed nearly with the ordi- 
nary “No. 4,” but as in addition to caoutchouce and shell-lac—the 
staple ingredients of the marine glne—this contained another and 
most important material, as applied to glass, it was agreed to call 
it “No. 4, G. K.;” subsequently the same valuable ingredient 
enters into the composition of every form of marine glue, so that 
“No. 4” is now a sufficient description of it. 
Another and very beautiful preparation of the marine glue has 
been made in this country, suggested by Dr. P. B. Goddard of 
Philadelphia. 
It consists of caoutchoue dissolved inchloroform by the appli- 
cation of gentle heat to the consistence of a thick mucilaginous 
paste; then add clean, carefully selected tears of gum mastic, 
until the composition become sufficiently liquefied to use with a 
rush, when it should be filtered to free it from the dirt always 
combined with the gums in question. The gum mastic not 
only readily dissolves in chloroform, but it is a somewhat curi- 
ous fact that it should reduce the thick solution of India rub- 
the iron plate, and their free < PF fhe 
= neta aced in sockets in oak serra tth ee 
tahogany board (6) the size of the iron plate, and % thick. 
