1829. ] 
whole is then to be well washed in clean 
water.—In this process, the mechanical dif- 
fusion through water is made to answer the 
same purposes as liquefaction by heat in the 
case of other metals—the earthy impurities 
being carried to the surface by their superior 
lightness, and the effect of fluxes being ac- 
complished by the solvent powers of water. 
The grey precipitate of platinum being thus 
obtained, in the form of a uniform mud or 
pulp, is now ready for casting, which is ef- 
fected by compression in a mould formed of 
a brass barrel, six inches and a half long, and 
turned rather taper within, so as to facilitate 
the extraction of the ingot when formed. 
The platinum is first subjected to partial 
compression by the hand with a wooden 
plug, so as to expel the greater part of the 
water. It is then placed horizontally in an 
iron press, constructed so as to give great 
mechanical advantage to the power applied 
to produce compression. The cake of pla- 
tinum is then to be heated to redness by a 
charcoal fire, in order to drive off all the re- 
maining moisture—afterwards subjected to 
the more intense heat of a wind furnace— 
and, lastly, struck, with certain precautions, 
while hot, with a heavy hammer, so as effec- 
tually to close the metal. The ingot thus 
obtained may, like that of any other metal, 
be reduced by the processes of heating and 
forging to any other form that may be re- 
quired: it may then be flattened into leaf, 
drawn into wire, or submitted to any of the 
processes of which the most ductile metals 
Varieties. 
209 
are capable. The perfection of the above 
method of giving complete malleability to 
platinum, is proved by comparing the spe- 
cific gravity of a fine wire of that metal ob- 
tained by this process, which is found to be 
21-5 with that of a similar wire drawn from 
a button, which had been completely fused, 
by the late Dr. Clarke, with an oxy-hydrogen 
blow-pipe, and which the author ascertained 
was only 21-16. A farther proof of the ex- 
cellence of the method employed by Dr. 
Wollaston is derived from the great tena- 
city of the platinum thus obtained, as deter- 
mined by a comparison of the weights re- 
quired to break wires made of this metal 
so prepared, and similar wire of gold and of 
iron. These weights he found to be, in the 
proportion of the numbers, 590—500 and 
600 respectively. 
Boring for Water.—Among the various 
discoveriesand improvements that have lately 
taken place, none haye been more conducive 
to the general benefit of mankind, than the 
lan now adopted of procuring water by bor- 
ing to the main spring, the success of which 
is certain, and the results thence arising are 
known to be advantageous. We have so fre- 
quently heard of the failure of this process, 
in consequence of its being undertaken by 
inexperienced operators, that we are glad to 
make known the names of the engineers 
who introduced the practice into this coun- 
try, and by whom it has been carried on 
with the greatest success, Messrs. Goode, of 
Plough Court, Lombard Street. 
FINE ARTS’ EXHIBITIONS. 
Britton’s Picturesque Antiquities of 
English Cities.—In the absence of more 
imposing and popular novelties in Fine 
Arts, we have much pleasure in directing 
the public attention to a work under the 
above title, two numbers of which have 
already appeared, and the whole of which 
(to be completed in six numbers) promises 
to supply a fund of interesting matter not 
inferior in value and variety to the numerous 
publications of a somewhat similar nature 
which had previously gratified and instructed 
thelover of picturesque antiquity, and ofarchi- 
tectural beauty and curiosity, from the same 
source. We have had occasion to notice, with 
commendation, some of Mr. Britton’s pre- 
vious undertakings in illustrations of the ar- 
chitectural and antiquarian riches of our 
island, buthave not hitherto beenable to give 
them that detailed attention which their com- 
parative interest and importance seem to 
claim for them. 
The object of Mr. Britton’s new work is 
in some measure, but not fully, explained 
_ by the tithke—“ Pictaresque Antiquities of 
fhe Engi Cities.” It is intended as sup- 
entary to and illustrative of a most in- 
teresting work edited by Mr. Britton some 
M.M. New Series.—Vox. VII. No. 38. 
time ago, entitled “¢ Views of the English 
Cities,” the drawings for which were so 
charmingly executed by Mr. Robson. The 
present work is intended to include all the 
minor features which the nature of the other 
work precluded from introduction: such as 
the ancient bars, gates, posterns, sally-ports, 
ruins of towers, dungeon keeps, city walls, 
remains of churches, castles, mansions, &c. 
&c.; in short, every thing connected with 
our English cities, which unites in itself 
the two characteristics of picturesqueness 
and antiquity.—Each number of the work 
is to include an average of from nine to 
twelve highly-finished engravings, besides 
wood-cuts of minor subjects, which latter 
are to be introduced into the page of the 
letter-press that is to accompany the illus- 
trations. 
Portraits of the Female Nobility in La 
Belle Assemblée.—In looking on one, in 
particular, of the portraits which form part of 
the embellishments of La Belle Assemblée 
for January and February, 1829, we can- 
not help exclaiming, jiat juslitia, ruat 
celum ! which we will, on this occasion, 
interpret, “ Let justice be done, even though 
in doing it we hold up to admiration the 
2E 
