112 PROCEEDINGS OF SOCIETIES. 
which, within the bean, causes the motion, but the perfect insect 
itself. Mr. H. Edwards, who was present, stated that he had never seen 
the insect before, as they had failed to arrive at such perfection in his 
hands, and his idea that it was a coleopterous insect was dispelled, for 
the little-winged, moth-like body was one of the Lepidoptera, without 
question. The matter was referred to Mr. Edwards for examination 
and report. 
Mr. Hanks was asked to report on a sample of so-called silver 
mud, presented by Mr. G. L. Murdock, and obtained from the silver 
springs lately discovered in Wasco County, Oregon. The sample 
gives a chemical assay of over $3000 to the ton, and it will be 
interesting to see what the microscope has to say about it. 
Mr. Hanks presented two specimens of minerals, being gold in 
hematite and talcose rock, from the Black Hills, Wyoming, a 
peculiarity being noted in the extreme fineness of the gold. 
Mr. Hanks also called attention to an interesting mineral which is 
only known to occur on the Pacific coast. It resembles scheelite, in 
which a part of the lime is replaced by oxide of copper. Professor 
Whitney, who first described it, has named it cupro scheelite. This 
mineral affords an example of the importance of the microscope in 
determinative mineralogy. When first discovered it was thought to 
be a mechanical mixture of scheelite with some copper mineral ; but 
upon a careful examination under the microscope it was found to be 
perfectly homogeneous. Subsequent discovery of crystals of cupro 
scheelite proved it to be a distinct and new species, as shown by the 
microscope. One peculiarity of this mineral is the ease with which 
the tungstic acid it contains can be isolated. Tungstic acid, combined 
with soda, forms tungstate of soda, the solution of which renders cotton 
cloth incombustible. It was suggested by Mr. Hanks that if tungstic 
acid could be produced cheaply, the theatrical managers could afford 
to prepare the cotton upon which their scenery is painted, and thus 
greatly lessen the danger from fire. Cupro scheelite is said to occur 
in considerable quantities both in Upper and Lower California. 
Mr. J. P. Moore exhibited a number of sheets covered with dupli- 
cate impressions of a drawing made from the microscope, with a new 
device, known as Zuccato’s papyrograph. He explained the simple 
process of the manipulation of the pen, ink, and peculiar paper on 
which the drawing is made, and suggested that scientific and other 
papers could be rendered more valuable by this system of multiplying 
the drawings of objects which might be referred to in any paper read 
before the Society. 
