TEMPLETONIA. 
to fall. The latter may find it below 50°, but it 
is not likely to be much below. If it should be 
thus low, the water of the above warmth would 
percolate speedily from top to bottom, and com- 
municate its heat during its progressive descent. 
The soil being dry, a portion of the water would 
be held by capillary attraction among the parti- 
cles of the former in the first instance; super- 
abundance to this would be carried off by the 
drainage at the bottom, making room for a fresh 
supply of water, imparting a farther elevation of 
temperature, till the whole became ultimately 
on a par with the rain, or very nearly so. This 
process might be greatly accelerated by stirring 
the surface, or inverting it, when well heated by 
the sun’s rays, so as to turn up a fresh portion 
to their influence. A considerable heat might 
be worked in by this means, even to the depth 
of the upper roots of the plants, and farther than 
that penetrated by the rain; but, the presence 
of the latter being necessary in other respects, 
it becomes a useful and appropriate conveyer of 
heat to a greater depth among the roots than 
could be accomplished in the open ground other- 
wise than by its soft insinuation. It is hoped 
that these remarks will be the means of directing 
attention to the necessity of an approximation 
of terrestrial and atmospheric temperature as re- 
gards the cultivation of exotics, and particularly 
that of the vine; and also to the use of water as 
a medium by which an increase of terrestrial 
heat is speedily communicated, when the former 
is properly applied, that is, when it is of a higher 
temperature than the substances with which it 
is brought in contact; and to the negative inju- 
rious consequences which follow its application 
at a low temperature.” 
TEMPLETONIA. A small genus of ornamen- 
tal, red-flowered, evergreen, Australian shrubs, of 
the genista division of the leguminous order. 
Two species, the retuse-leaved and the glaucous, 
both about two feet high, and blooming in spring 
and the early part of summer, have been intro- 
duced to the greenhouses of Britain; and they 
love a soil of sandy peat, and are propagated 
from cuttings. 
TENACITY OF METALS. Brick and stone 
are from their brittle nature never thrown into 
a state of tension, or employed for supporting 
pendant loads; therefore their properties in this 
respect have not been estimated or examined ; 
but the materials usually resorted to for this 
purpose, are bars of metal and chains, cylindrical 
or prismatic pieces of timber, ropes, and leather 
or raw hide; and the following tables show the 
power of those substances most commonly met 
with and used to support loads, the measure of 
their cohesion being the number of pounds avoir- 
dupois, which are just sufficient to tear asunder 
a rod or bundle of one inch square. From this 
it will be easy to compute the strength corre- 
sponding to any other dimensions. 
- TENACITY OF METALS. 
Ibs. 
Metals. 
. 20,000 
Gold, cast, varies between 60 OG 
‘ 40,000 
Silver, cast, do. eon 
{ Japan 19,500 
| Barbary 22,000 
Copper, cast, + Hungary 31,000 
Anglesea 34,000 
Sweden 37,000 
Cast Iron varies between Sone 
ordinary 68,000 
Bar Tron good 75,000 
best Swedish and Russian 84,000 
soft 120,000 
vligelt lee ati straw colour 150,000 
{ Malacca 3,100 
Banca 3,600 
Tin, cast, < block 3,800 
English block 5,200 
Do. grain 6,500 
Lead cast 860 
Regulus of Antimony 1,000 
Zine 2,600 
Bismuth 2,900 
Unfortunately these numbers donot accord with 
those of Mr. Rennie, who observes, “that the metals 
were held by nippers made of wrought iron, with 
their ends adapted to receive the bars, which, by 
being tapered at both extremities, and increasing 
in diameter from the actual section, and the 
jaws of the nippers being confined by a hoof, 
confined both. The bars, which were 6 inches 
long and + inch square, were thus fairly and . 
firmly grasped.” The following are a few of 
the experiments that were tried 30th of April, 
1817. 
lbs, avoir. 
4 inch bar of Cast Iron, cast horizontally, broke with 1,166 
3 Cast Iron, cast vertically, ua 1218 
x Cast Steel, previously tilted, S301 
a Blister Steel reduced by the hammer 8,322 
* Shear Steel do. do. 7,977 
ep Swedish Iron do. do. 4,504 
3 English Iron do. do. 3,492 
Be Hard Gun Metal (mean of 2 trials) 2,273 
A Wrought Copper reduced by hammer 2,112 
Se Cast Copper do. do. 1,192 
ie Fine Yellow Brass do. do. 1,123 
5 Cast Tin do. do 296 
is Cast Lead do. do. 114 
As all these experiments were made on 4 inch 
square bars, sixteen of which laid in close con- 
tact with each other, would constitute a square 
inch, it may be inferred that multiplying any of 
the numbers above given, would produce the 
amount of strain that would break a bar an 
inch square; but it is found in practice, that a 
number of small bars thus laid together, will 
bear a greater proportion of load than a single 
bar equal to the sum of all their areas. This 
anomaly is believed to proceed from the greater 
perfection with which small bars may be wrought 
and prepared than large ones, as all metals are 
improved in their strength by hammering or 
wire-drawing ; so the effect of hammering six- 
teen small bars separately, will add more to their 
strength, than hammering on a large bar equal . 
to the sum of their areas. Metals can only be 
improved in their strength by hammering or 
wire-drawing, in consequence of these operations 
