ferdages | 
1. Agenda, or a Colleétion of Obfervations and Refearches, 
the Refults of which may ferve as the Foundation for « 
Theory of the Earth. By M. De Saussure. 
[Concluded from Page 140.] 
CHAP. XXIII. 
Inflruments neceffary for the Geolegical Traveller. 
I. ‘Tue moft neceffary inftrument is the miner’s hammer, 
It will be requifite to have two, of different fizes: one {mall, 
to break fmall fragments of rolled pebbles, by holding them 
in the left hand while you ftiike with the right. Its weight, 
including the handle, ought to be about ten ounces. The 
other muft be larger, to detach fragments of rock, and to 
break large pebbles: its weight ought to be quadruple that 
of the {mall one. When I travel on horfeback, I have thefe 
two hammers fufpended from the bow of my faddle. 
1. A. Two ftone-cutter’s chifels: one fmall, of from a line 
to a line and a half, to detach {mall cryftals, or other objects 
of fmall bulk; the other, feven or eight lines. 
2. To try the hardnefs of foffils, a piece of fteel to ftrike 
fire will be neceffary ; alfo a triangular file, pretty fine, and a 
firong bedkin of tempered fleel. 
3. Nitrous acid, with M. De Morveau’s boxes of re- 
agents. 
3. A. An artificial magnet, in a cafe, with a fteel pivot 
on which it-can be placed, to try the magnetifm of foffils. 
4. A magnifying glafs of three inches focus, in order to 
enable the obferver to form a general idea of any foffil: an- 
other, of an inch focus, to examine its feparated parts; and 
one of five or fix lines for clofer examination. Thefe three 
magnifiers muft be always in the traveller’s pocket, or ready 
at hand: but, befides thefe, he muft have, for his clofet at 
home, a microfcope furnifhed with a micrometer. 
* 5. Telefcopes, to obferve inacceffible mines and diftant 
mountains. 
6. A pocket portfolio,-with prepared paper for writing ong 
Vol v; Ff With 
