70 
POPULAR SCIENCE REVIEW. 
fore from tlie common kind only in being non-poisonous. The 
other variety of match is a very beautiful invention. It is 
called the safety match, and well deserves its name. In our last 
number (page 522), we gave a short notice of this invention, 
and we will therefore only briefly refer to it here. The oxidiz- 
ing material alone is put upon the match, the red phosphorus 
being mixed with emery, and pasted on the side of the box ; 
the match is therefore not a match until it is brought in con- 
tact with this friction-paper, and the splints may consequently 
be trampled upon and littered about the house with perfect im- 
punity. No accidental ignition can possibly take place. 
We have thus briefly sketched a few of the valuable applica- 
tions of substances which some years ago were looked upon as 
utterly valueless. Coal-tar, rags, and bones, rise from the sewer 
and dust-heap, and are transformed by chemistry into costly luxu- 
ries, or necessaries of civilization, giving employment in their 
transformations to a large number of our working classes. 
Necessary limitation of our space has compelled us to omit all 
reference to other waste products which are now almost as 
extensively utilized ; but an attentive examination of the mag- 
nificent and unrivalled display of chemical manufactures now 
collected together at South Kensington, will convince the 
student, that to the chemist there is no such thing as a waste 
product, that which is so designated being to him a coffer of 
untold wealth, ready to yield up its treasures to any one apply- 
ing to it the master-key of knowledge. 
No. IV. 
THE PHILOSOPHICAL INSTRUMENTS. 
BY JAMES BREEN, F.B.A.S. 
S INCE the Exhibition of 1851, the improvements in philo- 
sophical instruments have been sufficiently various and 
important. Those which are now universally known were then 
undreamt of. The stereoscope has come into general use, and 
instead of the ghastly representations given by the daguerreo- 
type process, we have now solidity itself pictured forth in plain 
black and white ‘by the assistance of this little instrument. The 
collodion process, with! which it has been accompanied, has 
reached the utmost perfection. Photographs of the solar spots 
