Geology and Mineralogy. 69 
whe “individual volumes are small, and yet they Sere a megs 
amount of information compress sed into a small s space. For exam- 
ple the volume on the Electrical Light, after the discussgon of the 
theory of the incandescent and are light and the division of the 
electrical current, the different kinds of lamps are described under 
five heads: first, the incandescence lights based upon imperfect 
the are light ich are regulated by an electro-magnet; fourth, 
the electrical candl h, the lamps with inclined carbons 
Unde e five heads, some 80 forms of lamps are described, 
and in so far as the space allows, satisfactory discussion of these 
subjects 
II. GroLtogy anp MINERALOGY. 
Geological unification.—The Swiss “Comité @ unification 
Bibiogaen of which Prof. Renevier is President, held its third 
Meeting at Berne, on the 9th of April last, and was occupied with 
a discussion of questions submitted to c ‘in a circular 0- 
fessor Capellini of Bologna, President of the last Congress. These 
questions are a3 be acted upon at the meeting at Zurich in August 
next. The points of widest interest are the fo owing : 
In the ahi for the chart of Europe, which has 27 strati- 
graphical subdivisions, the committee proposes to have the number 
of divisions of the Cretsecous made three instead of two, and the 
Permian to have but one in place of two. The Gault and Ceno- 
monian make the middle Cretaceous. 
2) The uniting of the Rhetian to the Lias is recommended, to 
which in its rocks and fossils it is allied. In Switzerland the Rhe- 
tian is the first marine sles group after the Triassic which 
is ordinarily without fos 
(4) The oe of the Flysch from the Eocene and its union 
with the Oligocene would be impossible in the larger part of the 
rt es Alps. ~ The "Wessenalitec beds are often interstratified with 
e Flysch. 
(5) The Silurian group with its three divisions, of which the 
lower aoa * o the Cambrian, should be r epresented on the 
map by a single tee. of three different shades , as recommended 
recently by Professor Hebert before the Geolo ogical Society of 
ance, in a paper aiming to prove that the Cambrian should be 
responds to Barrande’s three Silurian faunas, the first, secon 
and third. [This recommendation heir ith reference to the Silurian 
accords with the its in North America. A separation of ned 
ambrian from the Silurian, hae What is above proposed, is 
