1797: ] 
The Patentee conceives they will prove 
of important fervice, in cafe of horfes 
taking fright, as the perfon or perfons 
within the carriage, may let down the 
fteps, and leave it without difficulty. He 
alfo thinks they would be of confiderable 
convenience to perfons who do not keep 
a footman, not only in private carriages, 
but in poft chaifes, ftages, and hackney 
.oaches. 
Messrs. Cuttirorp aNnp Co.’s 
Prano Forres. 
On the 31ft of January, 1797, Letters 
Patent were granted to Meffrs. Cunxi- 
FORD, RoLFr, and Barrow, of Cheap- 
fide, for their newly invented grand and 
fquare Piano Fortes. ~ 
The principle of this invention confifts 
in the fubftituting cof any vibratory fub- 
fiance in the body of the infirument, in 
lieu of the founding board, afually made 
of deal. The vibratory fubftance which 
has been preferred and fucceeded the beft, | 
is ox’s hide. prepared in the manner of 
vellum, and fecured from vermin and the 
ehanges of weather and climate, by fpirit 
varnifh and camphor. 
The vibratory belly has enabled the 
Patentees to apply a drum accompaniment, 
by means of pedals and of hammers, which 
act underneath. “This accompaniment has 
the full effeét of a double drum; with the 
peculiar excellence of being always in 
perfect tune, with every key in the in- 
flrument. © * 
Te will be readily conceived, by all 
perfons acquaintéd with the theory of 
found, thatthe application of an uniform 
vibrating fubftance, in the ftead of the 
deal boards formerly ufedy cannot fail to 
' produce a fuperior {weetnels and briiliancy 
ef tone. This mode of conttructing the 
Patents....Varieties, Literary and Philofophical. 
145 
beliy, alfo removes the inequality of tone 
in the feveral keys, that arifes from the 
irregular denfity and texture of the deal 
boards ; for, as the elafticity and tenfion 
of the ox’s hide is equal throughout, the 
vibration oppofed to the feveral ftrings 
mus be equal alfo, and the tone of every 
itring regular and perfect. 
Mr. Jacxson’s Door HEnces. 
On the sth cf December, Letters Pa- 
tent were granted to Mr. W. Jackson, 
lock-fmith, of Shire-lane, Temple Bar, 
for his improvement upon doors ; whereby 
the door fhuts of itfelf, and without 
found or noife, and wind is excluded from 
the room when the door is fhut. 
To effect the tirft of thefe objects i. e. 
the door fhuting of itfelf, the Patentee 
affixes a {pring above or below the hinge 
of the door, which {pring is turned by an 
axis, connected with the hinge or door. 
The return of the fpring to its natural 
pofition, again turns the axis, which being 
affixed within the hinge, or to the door, 
neceffarily fhuts it. 
The door fhuts without ndife, by means 
of a ipring affixed in the rabitted jamb, 
which vives way by the falling to of the 
door, and of courfe breaks the violence of 
the collifion. 
Wand is prevented from pafling under 
the door when fhut, by means of a:flap or 
drop made to fit the floor, which flap 
falls when the door is fhut, and rifles 
when the door 1s opening. The flap is 
made to rife aud fall by a {pring, which 
acts by the operation of a pim-in the 
inner edge of the door. 
One or all of thefe contrivances, may 
be applied to doors at the pleafure of 
the owner. 

LiTERARY and PHILOSOPHICAL; 
VAR bE a. & 
including Notices. of Werks in Hana, 
Domeftic and Foreign. 
*, Authentic Communications to this Article will always be thankfully received. 
AVERY interefting volume of Anecdotes 
of the moft celebrated Perloas connetied 
auith the Events of rhe french Revolution, 
will make its appearance in the courfe of 
three or four.weeks. 
Mr. W.R.Norcurt, fellow of the 
Linnean Society, has completed a work, 
which has cof him confiderable labour : 
A Cuart oF Botanistrs, from the 
earlieft ages down to the prefent time. 
qt is drawn on fo large a {cale, as to 
atlmit of having inferted, under the name 
ef every author, the titles of his prin- 
cipal works, the number of figures in 
each, the. dates of the laft editions, &c. 
It is now copying for the engraver, and 
will be ready for publication by the lat- 
ter end of thefummer. §” 
Mr. J. THELwattn is colleéting ma- 
terials for a third part of the “ Rze/is of 
Nawwre, againft the Ufurpations of Efta- 
bitifoments 3 which will be publithed t 
3 Auton 
Wa, 
