208 
formed part of Mr. Stevenson’s original 
design, and he, accordingly, lost no 
time in setting about the construction 
of a wooden beacon-house. This in- 
dispensable accompaniment to the 
works was successfully completed in 
the latter end of September; and, as 
the author (Mr. Stevenson) expresses 
it, robbed the rock of much of its ter- 
rors, and gave a facility to the works, 
which could not otherwise have been 
attained. 
“ The want of such an accommodation 
at the building of the Eddystone Light- 
house, where the smallness of the su- 
perficial dimensions of the rock did not 
admit of such an erection, formed one 
of Mr. Smeaton’s chief difficulties.” 
The cubical contents of the masonry, 
on the Bell Rock, is more than double 
that on the Eddystone ; but in only one 
instance does Mr. Stevenson seem to 
liave improved materially on Mr. Smea- 
ton’s plan; “ The principles upon which 
the floors of the two buildings are con- 
structed, are essentially different. At 
the Eddystone, the floors form so many 
domes; the arch stones of which are 
built in concentric rays, in the usual 
manner, and have a tendency or pres- 
sure outwards upon (against) the walls. 
To counteract this pressure, two strong 
chains are imbedded in the coarses, 
immediately below and above the floors. 
At the Bell Rock, the floors are so con- 
structed, that the pressure upon the 
outward walls is perpendicular; and 
they are so connected as respectively 
to form girths or binding frames to the 
building, at each story.” 
“In every thing else Mr. Stevenson 
cheerfully allows his obligations to his 
ingenious predecessor, insomuch, that 
the stone-lighter, which, of course, was 
continually employed, at the works, be- 
tween the rock and the shore, was 
called the “ Smeaton.” And it is re- 
corded, as an interesting incident, that, 
while the works were carrying on, they 
were visited by Mrs. Dixon, daughter 
of Mr. Smeaton. 
Fearing, Sir, that the interest I feel 
in works of this description may al- 
ready have led me into too great a 
length, I remain yours, &c. 
London, 9th March. 
> i 
fo the Editor of the Monthly Magazine. 
“Sir: : 
‘A. CORRESPONDENT, in your 
last Number (p. 118), ,who. de- 
scribes, from Dr. Brewster’s Journal. of 
Science, a very ingenious mode of de- 
THERMES. 
Radiant Heat.—Nuisanee of Cart-whips in the City. 
(Apr. 1, 
ciphering medals, &c., having adverted 
to “the well-known fact, that rough 
surfaces radiate heat more freely than 
polished ones,” —the following addi- 
tional references may not be unaccep- 
table to your readers, 
The fact was thus stated by Professor 
Leslie, in his “* Inquiry into the Nature 
of. Heat :”— 
““ The power of the blackened side of a 
canister being denoted by 100, that of a 
clear side was 12. Another side, which 
had been slightly tarnished, was scraped to 
a bright irregular surface. The effect was: 
now 16.—Another side was ploughed, in 
one direction, by means of a small toothed 
plane iron, used in veneering, the interval 
between the teeth being about one-thirtieth 
or one-fiftieth part of an inch: the effect 
was farther increased to 19.~-The first 
smooth side was now scraped downwards, 
with the point of a fine file: its effect was 
23. But the filing being repeated, and 
more thoroughly covering the surface, the 
effect rose to 26.”’—>p. 81. 
This curious property, Mr.W. Ritchie, 
A.M., Rector of the Academy at Tain, 
illustrates, “in a novel manner,” in the 
January Number of the Edinburgh Phi- 
losophical Journal, by a very simple: 
diagram, and demonstration; which, 
however, hardly makes the matter clearer 
than the Professor himself has done: 
but, by following up the subject, Mr, 
Ritchie deduces, 
“That the increased effect upon the 
focal ball, when a striated surface was (is) 
used, does not depend upon the increase of 
surface, but upon the quantity of heat re- 
flected by the sides of the furrows.”’ 
5th March, 1825. 
—==_>>—— 
To the Editor of the Monthly Magazine. 
Srr: 
EEING, so frequently, short letters 
and inquiries, on a variety of’ sub- 
jects, in the Monthly Magazine,—I take’ 
the liberty of requesting, that you will’ 
stop a corner in one of your sheets with 
the following query :— ; 
Persons walking the crowded streets 
of this vast and growing metropolis, are 
frequently struck with the nuisance of 
long cart-whips,—particularly in those 
narrow streets, emphatically said to be 
“in the City: they are very annoying; _ 
so much so, that I feel compelled to 
enter my feeble protest against them, 
and earnestly to ask, Whether a remedy 
for this nuisance cannot be found?—~ 
Yours Outen won. 2 
London, 9th March. 
