Short Papers and Notes. 225 
hours. Each diver has a little bag around his neck, and a 
peculiar hook, with which he pulls up sand, and every piece of 
amber that he finds is thrown into his bag. An encouragement to 
the diver is that if he finds a piece of amber he is entitled to a 
prize of ten, twenty-five, or fifty cents, according to the size. 
While the divers are below in the sea, engaged in hunting for 
the amber, the miners are just as busy on land, for it seems that 
the same stratum of the green sand runs, perhaps for thirty miles 
or more, into the land. The opening of the mine is perhaps a 
thousand feet from the shore, and it is necessary to go down about 
one hundred and fifty feet, which is some thirty or forty feet below 
the leve] of the sea. To keep the mine as dry as possible, there 
are several pumps working day and night; and to prevent the 
earth from falling in, the passages are propped up by logs of wood. 
There are about forty miles of passageway in these mines, and 
there are about seven hundred men employed for the various 
departments. As soon as a passageway is opened, a track is laid, 
and on this track there runs a little truck, which holds perhaps 
half a ton of sand. The miners simply cut out the sand and fill 
the truck. It is then brought to the surface, where the whole 
contents is thrown into a long trough filled with rushing water, 
which separates the sand from the amber, which is caught by nets 
of various sizes. The amber is then cleaned by machinery, and 
assorted according to its quality and purity. The writer believes 
himself to be the first American who ever went down into ‘the 
amber-mine. 
Short Papers and Notes. 
Hotes on Fresb=water Sponges. 
By V. A. LatHam, F.R.M.S. 
Since the time of Linnzeus much has been learnt about these 
organisms, better and more complete knowledge coming with the 
improvements in microscopy. Such men as Bowerbank, Grant, 
Carter, and Mills have given the subject much thought and _ work. 
Europe, Asia, Africa, and the two Americas have contributed to 
the number of species. Quite a number of remarkable sponges 
have been found in the Amazon River, while Fairmount Dam on 
Schuylkill River, in Philadelphia, Pa. has, I believe, been 
considered one of the richest localities in the world for fresh- 
water sponges. Perhaps the earliest mention of fresh-water 
sponges is that of Leonard Plukenet in 1696. These sponges, 
unlike those of commerce, possess a skeleton whose fibre is 
entirely composed of siliceous spicules, bound together by a very 
