HEAT-REGULATOB.

649

.These “ suspenders” are composed ot thin plates of copper, bent into the retiredCa i t *' at ’ Sj near 'y resembling that of a hat block, and made in such a manner as to hePable of contraction and expansion to suit different sized hats, and keep themsteaded, which may be altered by the workmen at pleasure, when it is required toace the hats upon them, or remove them therefrom. The dveing-frame at fig. 546 isawi * w hh only, two of these “ suspenders,” in order to prevent confusion. One of thesespenders is represented detached at fig. 547, which exhibits a side view; and fig. 548co r °- nt v ‘ ew °f l h e same. It will be seen by reference to the figure, that the suspendersa j lst .pf two distinct parts, which may be enlarged or collapsed by a variety of means,sn W *'' c * 1 means may be suggested by any competent mechanic. The two parts of thejv P en ders are proposed to be connected together by arms g g, and at the junction ofref e arms a key is connected for turning them round when required. It will be seen onerence to the front view, fig. 548, that the “ suspenders” or substitutes for blocks, arelim at to P or crowif part of the hat; this is for the purpose of allowing the dyeing,. or to penetrate.

0 j. r °m the mixture of copperas and verdigris employed in the hat-dye, a vast quantityWe**! ° c kreous muddy precipitate results, amounting to no less than 25 per cent, of thetor t C0 PP eras - This iron mud forms a deposite upon the hats, which not only

s- ° ae s the-fine filaments of the beaver, but causes both them and the felt stuff to turnso k ” a rusty brown. There is no process in the whole circle of our manufactures.barbarous as 6'at of dyeing stuff hats. No ray of chemical science seems hitherto toj.. ® Penetrated the dark recesses of their dye shops. Some hatters have tried to removeevil COrros * ve brown ochre by a bath of dilute sulphuric acid, and then counteract theefil e ^ ect of the acid upon the black dye by an alkaline bath ; but with a most unhappy(, r ct- Hats so treated are most deceptious and unprofitable; as they turn of a dirtyjJ'Ji hue, when exposed for a few weeks to sunshine and air.

Cer , . ALDS, is the harness for guiding the warp threads in a loom; that is, for lifting ain» am nutn her of them alternately to open the shed, and afford passage to the decussat-threads of the shuttle. See Weaving .

AARTH (Foyer, Fr.; Heerde, Germ.) is the flat or hollow space in a smelting fur-J a u P°ti which the ore and fluxes are subjected to the influence of flame. See Copper ,JjJ, “^t'ALLORGY, &c.

l he ’' s l *’ at P ow er or essence called caloric, the discussion of whose habitudes withjjp 1 lerent kinds of matter belongs to the science of chemistry.f ur A-AT.REGULATOR. The name given by M. Bonnemain to an ingenious apparatusp lc Seating the temperature of his incubating stove rooms. See Incubation, Arti-■p, G f°r the manner of appljing the Heat-Regulator.in e[a , e obstruction of the regulator is founded upon the unequal dilatation of differents ®y the same degree of heat. A rod of iron x, fig. 549, is tapped at its lower549 end into a brass nut y, enclosed in

a leaden box or tube, terminatedabove by a brass collet z. Thistube is plunged into the water ofthe boiler, alongside of the smoke-pipe. (Fig. 549* is a bird’s-eyeview of the dial, &c.) The ex-pansion of the lead being morethan the iron for a like degree oftemperature, and the rod enclosedwithin the tube being less easilywarmed, whenever the heat rises tothe desired pitch, the elongationof the tube puts the collet z incontact with the heel a, of thebent lever a, b, d; thence thel he mcrease of heat lengthens the tube anew, and the collet lifting the heel ofr ?Htiv e ] ae P r esses its other end d through a much greater space, on account of thes bil; s 0n en ?ths of its legs. This movement operates near the axis of a balance-bar e,blitted df i an ^ there by increases the extent of the movement which is trans-

°r cuts off?i t0 llle “ on s kewer v. This pushing down a swing register diminishesJbe tempo 116 acces . s °f air to the fire-place. The combustion is thereby obstructed, andThe eount ralUr - e by degrees, the tube shrinks and disengages the heel of the lever.

7 raisi n< , e [P 0lse 10 l * le balance beam c, raises the other extremity of this beam,

collet’of X Gn k * ever as much as is necessary to make the heel bear upon

Se ction to th 6 tU ° e * The sw * n ? register acted upon by this means, presents a greatere passage of the air; whence the combustion is increased. To counter-