SCIENTIFIC SUMMARY. 
339 
the flue of a furnace supplies some interesting objects for the Microscope. 
Besides other bodies contained in this coal ash may be seen a number of 
curious-looking objects which vary in size and colour. The majority of 
these bodies are spherical, and when separated from the irregularly shaped 
particles forming the bulk of the dust they become interesting objects for 
the microscope. Some of these are as perfect in form as the most carefully 
turned billiard balls, and have a brilliant polish. The various colours which 
these globules exhibit give additional interest to their examination. Some 
are transparent crystal spheres, others are opaque white, many are yellow 
and brown, and variegated like polished agates or cornelian of different 
shades. The most abundant of the highly polished balls are black ; there 
are others which look like rusty cannon balls — some of these have an aper- 
ture in them like a bombshell, and many are perforated in all directions. To 
obtain these objects the dust should be washed in a bowl and all the lightest 
particles allowed to float away; the remainder consists of fragmentary 
crystalline and ferruginous substances ; mixed with these are the polished 
balls described, which, under the microscope, by a brilliant reflected light, 
look like little gems. To separate the spherical bodies from the irregular 
ones, it is only necessary to sprinkle some of this material on an inclined 
glass plate, and by gentle vibration the balls roll down, and can thus be 
collected. — Vide Chemical News, June 21st. 
PHOTOGRAPHY. 
Photography at the Paris Exhibition . — On the whole, the art-science of 
photography plays its part well at the great French International Exhibition, 
and in the collective displays of various nations we find its numerous and 
diverse applications, improvements, and modifications fairly represented. 
The Austrian collection is a very attractive one and contains some of the 
very best specimens of photo-lithography yet produced ; its specimens of 
portraiture from life-size downward are of a very excellent character, and, 
like those of France, Prussia, and Russia, are decidedly superior to the 
English. In the Darmstadt contributions are some interesting specimens by 
Dr. Reissiz exhibited to illustrate his theory of photogenic action. In the 
Prussian department a large portrait lens attracts attention ; it is four- 
teen inches in diameter and covers a square of thirty inches. The French 
department contains some interesting specimens of photographic-engraving 
process, of enamelled photographs, and of enlargements from microscopical 
photographs, amongst which is one of a flea enlarged to the size of a small 
pig. Amongst the novelties and applications of photography to decorative art 
are photographs of a singular character, illustrative of a new process called 
“ Chrysoplasty.” They represent goldsmiths’ work, ancient armour, draperies 
embroidered with gold and silver, bronze statuary, philosophic instruments, 
&c., and are apparently in the same metals as the originals. This process is 
a secret one, but the inventor, Mr. Bceringer, is prepared to produce such 
photographs from any negatives which may be sent him for that purpose. 
He is at present making a large collection of specimens from antique curi- 
