59
tl >e brieftaki: -
ht light emitted from lime ignited by the oxy-hydrogen flame; as is practised inT >ng the Daguerrotype portraits at night.
all the photographic pictures the lights and shades of the object are reversed;
they may be made conformable to nature by rendering the paper transparent withjjte wax scraped upon its back, melting this in by rubbing it with a hot smoothing-aPter * s placed between two sheets of common paper, then laying it upon paper1 ah e< * bromide of potassium, and exposing it to sunshine. Portraits are bestth ky means of a lens, whose focal length is three or four times only greater thana 'diameter of the aperture.
(h^NDLES. Messrs. Hempel and Blundell have given a very minute account ofPat proce3S for making palm-oil, stearic and margaric acids, in the specification of theirtent for this mode of manufacturing candles :—
Pal ^beir first process is called crystallization , which consists in pouring the meltede j*ht-oil into iron pans, and allowing it to cool slowly, whereby, at about 75° F., thel ne separates from the crystalline stearine and margarine.
Uj, ‘ The concreted oil is subjected to the action of an hydraulic press, in order to sep-, te the elaine from the solid fats.
aj • This process is called oxidation. To 104 lbs. of the stearine and margarine,<jj[. 1e d in an iron pan, about 12 lbs. of slaked and sifted quicklime are added, withso'^nt stirring, during which the temperature is to be slowly raised to 240° F., and'p|. f llE jintained for about three hours, till a perfect chemical combination takes place.
is shown by the mass becoming thin, transparent, and assuming a glassy appear-*t tf w ben it cools. The fire being now withdrawn, cold water is added very graduallyH rS *’ brisk stirring till the whole mass falls into a state of powdery granulation,. e ® it is passed through a wire sieve to break down any lumps that may remain,btu \® e P ara ti° n °f the stearic and margaric acids, from the lime. For this purpose, asSt( j “ muriate of lime (chlorcaleium) is taken as will, with its equivalent quantity of4 C i?buric acid (8 lbs. of dry chlorcaleium require 7 lbs. of the strongest sulphuricScid ’ l ,ro| iuce as much muriatic acid as will dissolve the lime combined with the fatt te a8 i and therefore that quantity of muriate of lime dissolved in water must be3 tat ^ w bb as muc b sulphuric acid as will saturate its lime and throw it down in thePorr su lph ate of lime. Add the supernatant solution of muriatic acid in such pro-liis ° n to tbe stearate and margarate of lime as will rather more than saturate thefQj’V Three pounds of muriatic acid diluted with 9 lbs. of water are stated as enoughc °ta °b lime. This mixture is to be let alone for 3 or 4 days, in order to insure thea s jPwte separation of the lime from the fat acids; and then the mixture is heated soSuit; btelt and cause them to separate in a stratum on the top of the liquid. The re-muriate of lime is drawn off into another tub, and decomposed by its dose ofg Pjdc acid, so as to liberate its muriatic acid for a fresh operation.
The fat acids, being well washed by agitation with hot water, are then set to coolat '-‘■ystallize, in which state they are subjected to the action of the hydraulic press,tem perature of 75° F., whereat the margaric acid runs off from the solid stearic
^ eac hing. The stearic acid is taken from the press, and exposed upon water intuj®®^hallow vessels placed in the open air, where it is kept at the melting tempera-tli 0111 ^ ^ hours, stirring meanwhile, in order to promote the blanching action
Ve ssel atmos Ph ere - The margaric acid is bleached in a similar manner in separate
ftgjt ' fofiwing process . The fat is warmed again, and poured in a liquid state into anb W m "- tub i where, for every 1,000 lbs. of the stearic acid, about lbs. of common2O0ii° x hte of manganese, and 40 lbs. of concentrated sulphuric acid, diluted withthe h S * P ur e water, are to be used. This solution ( <e mixture”), while warm fromt ubt ea J evolved in diluting the acid, is placed in a suitable vessel above the agitatingbe "he stearic acid being at the melting point, in the vessel below, agitation is towith a revolving shaft, while the mixed manganese and acid are run slowlyThe )r ! nto the whole be well mixed, which generally requires about two hours.
8^, ? ss * s flowed to lie in this state for 48 hours ; after which it may be boiled byis m tor 2 or 3 hours, when it will be sufficiently refined. The sulphuric acid, whichihffe x e bottom, is now run off, and the stearic acid which remains is well washed withor i.'icp a ^ er * It is then put into large conical vessels of stoneware, enclosed in a box
VeriV 51 ’ ^ ept
k
warm by steam-heat, and lined, with conical bags of suitable strong
bp ? ^ a P er ) through which, being warm, it finds its way ; and when the stearic acid8tea ric U ^ 1Us filtered, it is run into blocks, when it will be found to be a beautifulO a t , acit * °r palm-wax, and is ready to be made into candles in the usual way.that process with manganese and diluted sulphuric acid, it maybe observed,
the^ft^^tion or chemical action takes place between them, and their joint use seems
ttost problematical. The patentees proceed to describe other processes of