45a

[Unit!®

Class 10.—PHILOSOPHICAL, MUSICAL, HOROLOGICAL ,North, North Central, and South Central Galleries.

sugar boiling, or situations where space is an object. (See

fig. 2.)

Fig. 2.

Bakers Steam ami Vacuum Gauges.

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nsis

New steam gauge. Eain gauge, upon a simple plan.

Thermometric alarum, for giving an alarm at any re-quired temperature; useful in case of fire,' overheating,&c. It consists of a bent glass tube, with a bulb at eachend, one of which is open to the external air, a certainquantity of mercury is poured into it. The ethervapour in one bulb acts as a thermometer, and by itsexpansion displaces the mercury, which flows into theother; the tube rests upon a pivot, and is by this move-ment overbalanced. The brass tube over the glass onecontains a ball, which then rolls down and falls upon alever in the upright pillar, which sets the clockwork inmotion, giving an alarm which will continue for some time.It will also act as a thief-alarum, by means of wires beingfixed from it to the doors and windows.

Horticultural and other thermometers. Barometers,for the working classes. Glass hydrometer for testingthe strength of spirits, in a box, with a thermometer.Glass saccharometers, for testing beer. Glass lactometer,for showing the quality of milk; also the per centage ofcream by measure. Urinometers, fitted up in variousways, with bottles, lamps, and test tubes.

399 Chamberlain, William, jun., St. Leonards-m-Sea—Inventor.

Large model of a patent machine, to be used in re-cording votes by ballot.

Model of a similar patent machine, for taking votes ondivisions.

401 Hughes, William, Governor of the Blind Asylum,Manchester —Inventor.

Registered portable typograph. A new mechanicalcontrivance for the use of the blind. See the annexedcut.

By the aid of this instrument persons who can read thecommon embossed Roman letters (even of double theordinary size) may communicate, by letter, after a fewminutes’ instruction. This typograph is calculated togive, at pleasure, any letter or figure in the eighth partof an inch; and, if required, a blind person may withease put sixty-four distinct letters within the space ofa square inch. The typograph is applicable to many

other purposes, such as printing uniform labels f 01museums, &c.

Hughes’s Registered Typograph .

The typograph, a similar instrument, constructed f° rembossing, or printing in relief.

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402 Wilton, William, St. Day , Truro —Manufacture^Fox’s magnetic dip and intensity instruments,

Set the

sizes, for showing the exact dip of the magnetic needjc

and for measuring relative magnetic intensities,annexed cut.

Fox’s Magnetic Dip and Intensity Instrument.

This instrument consists of the following parts

.ate*

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1st. Of a horizontal plate, traversing within a gramimb mounted upon a tripod of brass, and

limb

screws to the true level, by a ground-glass spirit I

2nd. Of a strong ring fixed at right angles to ^former, within which are two graduated limbs, the <> ^one divided to 15^, and the inner one to 30’,fixed to the instrument as to direct the eye in reading^,from the points of the needle, thereby avoiding elfrom parallax. ,.j e ,

3rd. Of a solid back with a graduated limb out ® a( jeand an armature carrying a telescope, with verniersto revolve thereon. 0 f

4th, Of a concentric ring, revolving in the cen sthis, and carrying a plate with bracket and app eufor the needles. gte el

5th. Of a magnetic needle attached to a put

axle, terminating at the extremities in very “i’ggfitperfect cylinders of hardened and polished steel; t ^,j t ],into jewelled holes, which may be moved arou ’!, e jn ftthe concentric ring, and which suspend the nee ;t

vertical plane, making it very steady, yet aimperfect freedom to settle in the magnetic dip- _ ^ so

6th. Of a small brass stud projecting behind, ^fixed as to form a continuation from the axle^ as ®needle; against this, is employed a small ivory “ e( jj e ohrubber, which counteracts the friction of the ne

its axle.

ax* e .

of

7th. Of a fine concentric brass pulley on thethe needle, over which passes a fibre of unspo_ e ofcarrying a small hook at each end, for the p al T stn! fitesting magnetic intensities by the employment 0 . str u-weights, a series of which are furnished with thement. & into

8th. Of a pair of small cylindrical magnets 11 .^jiidj,brass tubes, and made to screw into the armature ^ offwhen the venders of the armature are placed t< L je0 thethe same degree as the points of the needle, ^ ^dpoints of these magnets are exactly opposite the