256 
minute fand-glaffes now commonly ufed 
at fea, when the log is thrown for the 
purpofe of afcertaining the fhip’s rate of 
failing, Mr. Gould procures glafies to 
‘be blown about the fhape and fize of an 
orange, or hen’s-egg, with a {mall hole 
at each end. ‘hele holes are to be fo 
enlarged, by means of a round file, till 
the glafs will empty itfelf.at one end in 
half_a-minute, and at the other in fifteen 
feconds; thereby. making one of thefe 
glafles anfwer. the purpole of two fand- 
glafles. Some of them are made to mea- 
fure time at one end only, leaving the 
other open, f that they may be more 
eadily filled. When they are prepared 
for use they are filled with water, .by im- 
merfing them in a bucket, or other vef- 
fel of water, and the water prevented from 
efcaping till the proper time, by placing 
the thumb over the hole at one end of the 
glafs. They are ufed in the fame man- 
ner, and for the fime purpofe at fea, as 
the common fand-glafles are. They are 
much more correét, and uniform in their 
action, and lef liable to accident. ‘They 
may alfo be made to ran a longer time, 
and to anfwer feveral purpofes on land as 
well as at fea. hel See 
—a— 
MIR. ROBERT KIRKWOOD’S (EDIN- 
BURGH) jor certain IMPROVEMENTS 
en the COPPER-PLATE PRINTING- 
PRESS, 
In the ufval method of copper-plate 
printing, the paper on which the impref 
fion is to be made, being placed on the 
plate, and both laid on a plank, the 
whole are pafied through between two cy- 
hinders, which prefs on one another, revol- 
ving on axes. / 
In printing common work the preffman 
pafies the piate and paper through, and 
returns them to himfelf, remaining in the 
fame place for convenience. But for a 
more peife&t imprefiion, the preffman 
pais the plate and-paper only once thro’, 
that is, from himfelf to the other fide of 
tie prefs, and then, going round, carries 
back the plate and impreffion to his for- 
mer fituation. 
The improvements made by Mr. Kirk- 
wood are as follow: ; 
The circular form of the upper cylin- 
der is interrupt.d, broken, or altered, by 
x part of it being in fom de sree flattened 5 
fs that when ail the remaining circular 
part of ix, in tarnmg round, has borne on 
tbe plate, the flat part is then prefented to 
the plate, and the prefiure on the plank 
aa i 
~ 
New Patents lately enrolled, 
fod. ij 
and plate is at an end, and they are res 
turned by machinery to the prefiman, or to 
their former pofition, where he remains 
to receive them, and repeat the operation. 
Another means of improving copper- 
plate printing preffes is, to retain the 
circular form of the upper cylinder, and 
make interruptions on the lower one, at 
the fame time fixing two rollers or other 
fupport for the plank to be drawn back 
upon, while unfupported by the Jower cy- 
lindey. : . 
A third means of producing the defired 
effect is to preferve the circular form of 
the upper and under cylinder, and raife 
or fuipend ‘the upper cylinder, or lower 
the under cylinder, by a lever on each 
fide of the prefs, or other mechanical con- 
trivance, in order to allow the plank and 
plate to return to the workman without 
pafiing twice through the cylinders, or 
obliging the workman to go round the 
prefs, or reach over the upper roller for 
his plate and impreffion. 
Whea required Mr. Kirkwood adds a 
movement, by clock-work, for the pure 
pofe of nambeiing the impreffions taken. 
=e 
MR. ROBERT MASON’s (PORTSMOUTH) 
jor IMPROVEMENTS 0” @ COMMON. 
WAGGON, whereby the fame may occas 
Sionally be fepavated and ufedas two caris. 
This waggon is formed by two diftin& 
frames, termed the fore and hind carts, 
as they correfpond with the fore and hind 
parts of a common-waggon, with the ex- 
ception only as to the pole, thofe carts 
having one each, that of the fore cart 
turns upwards from the main pin on the 
under fide thercof.. A roller may be 
fixed for the {weep of the heunds to lock 
on, until it reaches the back fthud-lock, 
to which it is fecured, and extends about 
four inches behind its. extremity. 
pole of the hind cart is to proceed from 
the hind fhud-lock, through the axletree, 
The 
/ 
turning upward to the front fhud-lock, — 
to which it is fecured. As the projec. 
tions of the two poles are to pafs clofe to 
each other, it is neceflary that one fhould 
incline to the right, and the other to the 
left. ‘ 
Fhe pins that pafs through the fhude - 
locks and projeGtions of the poles by 
which the carts are in part united, areto 
be removed, and pafied through the bed ~ 
in‘c the fore axletree, one on each fide of 
the main pin, to prevent its locking when 
ufed as a cart. 
eyes 
The fides and fhud-lecks | 
of the carts are united with hooks and — 
» ea) | 
. 
