Wiel] 9 Account of the late. Tiherwus Cavallo, F. B.S. 
the. study of fature displaying, superior at-, 
tractions, he was seduced from the accompt- 
ing-house, to embrace the leisure of a philo- 
s@phical retseat 5 and acquired a well-merived, 
reputation asa digester and elucidator of phis 
lasophical discoveries, In che. year 1779, he 
was admitted.a member of the Neapolitan 
Academy of Sciences, as well as of the Royal 
Society 9: London. "Me publicati6ns of Mr. 
Cavallo have been as follows:—A Complete 
Treatise of Electricityin Theory and Practice, 
with Orietnai Experiments; one volume, 
octavo, 1777, lenlarged. to. three volumes it, 
1795.)~—An Essay on the Theory and Prac- 
tice of Medical Electricity; one volume, 
octavo, 1780.—A° Treatise on the, Nature 
and Properties of Air, and other Permanently 
Elastic Fluids, (with an Introdueti-n to Che- 
mistry 3) one volume, quarto, 1781,—-The 
History and Pyectice of Aerostation; one 
volume, octavo, 1785.—Mineralogical Lables; 
felio, (accompanied with an “octavo explana- 
tory pamphlet,)1795.—A Treatise on Mag- 
netism, in Theory and Practice, with Original 
Experiments; one volume, ociavo, 1787. 
—Description and Use of the Telescepical 
Mother-of-Pearl Micrometer, invent<d by 
T. C. a pemphiet, octavo, 1793 —An Essay 
on the Medicinal Properiies of Factitious 
Airs, with an Appendix on the Nature of 
Blood; one volume, octave, 1798.—For the 
progress and difiusion of ‘science, we are in- 
debied not more to the happy efforts of ori- 
ginal genius, than to the judicious industry 
ef those authors. who frem time te time, 
employ their talents bn digesting and eiuci- 
dating successive discoveries. The distin- 
guéshed rank which Mr. Cavallo held in this 
useful cliss of philosophic labourers, is suili- 
ciently knows. His treatises on popular and 
interesting branches of physics, may be justly. 
esteemed ine best elementary works which 
are extant in our language. They possess 
every requisite of such performances, persol-, 
cuity of style, proper selection of materials, 
and clear arrangement. The merit of Mr. 
Cavallo is not, however, the merit of a merely 
judicious compiler. He never aspires indeed 
to furm new and comprehensive views; yet 
he generally improves, in some degree, the 
stock o vafuable facts, by his own occasional 
experiments. More than thirty years have 
elapsed since the Treatise of Electricity was 
first presented to the public. During the in; 
tervalit.has passed.through repeated Impres- 
sions, 2nd the recent discoveries ia eiectri- 
city affording large additions of curlous and 
useful matter, the work -was sucgessively 
augmented from one volume to thige. It is 
unquestionably the neatest, the clearest, and 
the most sensible, elementary treatise to be 
found on this popylar science; aud it is ex- 
cellently adapted to furnish the’ mind with 
those) brilliant images and.facts, which pro- 
voke inguisitive genius to closer and more 
protound researches. The principahintenation 
@f the Essay on the Theory and Practice of - 
a 
s+ 
87 
Medical. Electricity, was to. 2nnounte the, 
Improvements then Jately made in the ade) 
ministration of this new and singular medi« 
cine. (Phe Treatise on Air is a very useful 
performance, especially when considered ja 
teference.to the state. of this interesting: 
branch or philosophy at the time of ics pab= 
lication. ‘Dbe yreat_ number and variety, as 
well as the impertancey of the discoveries 
then jately made by Dr. Priestley, and other 
philoso hers here and on the Continent, upom 
this. subject, and in various other branches of 
experimental philusophy connected. with it, 
rendered a collection“ci the most importanr 
facts and coservations, methodically arranged 
under distinct heads, peculiarly useful to those 
wishing to cultivate this extensive and interes 
esting. pant of experimental knowledze. A 
somewhat similar, but smaller compilation, 
had been belore executed by the ingenious ays 
thor of the Treatise on Gases; as likewise f 
M. Macquer, in the last edition of his Dicti., 
onary of Chemistry; but Mr. Cavallo pers 
formed the task in a much more comprehen- 
sive aud particular manner, his object having 
been to instruct those possessed of little or. no 
previous knowledge of the suadject. Lie jas 
dicious and entertaining volume on Agraw 
station, is divided into two parts 5. one come 
taining the history, and the other the pracs 
tice, of the art. The first. etperiments on 
this sulject appear to have been made by Mes 
Cavallo himself, early in the year 4782; and 
an account of them wes read to. the Royal 
Society on the 20th of june, in that yates 
They were not. inceed successful, because 
they were made on too small ascale;.and it 
is wel! known that the Monzgolfiers succeedled 
in France, by happily. making tke trial ia 
large, on a principie by them misundersteos, 
His publication, however, laid the public 
under considerable obligations.to Mr. Cavalle, 
as no one in this country had yet written sole 
entificslly upon this few and. philosophic 
art. in the mineralogical tables the ex¢el- 
lent system, sketched by Cronstedt, correcred 
and-improved by Bergman, and tarther en- 
larged by Kirwan, is disposed in two very - 
useful tables, each filling one side of a large 
sheet. One of them contains tle four classes 
of minerals, divided into ormlers and genera, 
with the ;rincipal) properties of each: “the 
other, all the particular.species and. varieties, 
ranged -under the. respéctive divisions 5 those 
which are compounded of two oF more ingeey 
dients, being pise:d‘in that class or order to 
which $heir principal ingredient, belongs, 
The treatise on magnetism exhibits a coma 
prehensive view of our knowledge on thar 
subject, The inzenious auther his collected 
from former writers whatevar wus useful or 
cutious,, and added maav new observations, 
He has disposed the various particulars in 
that order, which naturally leads the reader 
from the sinyplest to, the most intricate part 
of the subject, by the paths which are plain- 
est and shortest. It. is not quite forty years, 
; i \. siace 
