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le by the screw c； This block is only used for holding the plate while undergoing the first operation in cleaning。 ＇hipho_11。gif＇
Fig。 11； shows the form of Lewis' newly patented plate vice； which for durability； simplicity and utility is preferable to all others。 It consists of a simple platform and arm of cast iron； the former； a； having a groove； d； in the centre for fixing the different sizes of plate beds； eand the latter supporting the leaves； e f。 On this vice which is secured to a table； or bench； the plate receives its finishing polish with rouge； or prepared lampblack。 Mr。 Lewis gives the following directions for its use。 〃As the cam wears tighten it with the adjusting screw （g） so as to allow the lever （f） to fall back into a horizontal position； the plate being in its place at the time。 Oil the wearing parts occasionally。〃
Some Daguerreotypists； however； use a foot lathe with buff wheels of various forms； but this vice is sufficient for all ordinary purposes。
V。 COATING BOXES。The usual form for iodine and ＇hipho_12。gif＇ ＇hipho_13。gif＇ bromine boxes is see； at figs。 14 and 15。 They are far superior to those in use with the English operators。 Each consists of a wooden box （a；） having firmly embeded within it a stout glass jar （c）； the edges of which are ground。 Over this is placed the sliding cover b； double the length of the box； one half occupied by a piece of ground glass （e）； tightly pressed upon the glass pot by a spring （i） beneath the cross bar g； and fits the pot so accurately that it effectually prevents the escape of the vapor of the iodine； bromine or other accelerating liquid contained therein。 The other half of the lid is cut through； shoulders being left at the four angles for the different sizes of frames； designed to recieve the plate while undergoing the coating process。 When the plate is put into the frame； the cover b is shoved under the second lid h and when coated to the proper degree； it resumes its former position and the plate is placed in the holder of the camera box。 To test the tightness of the box； light a piece of paper； put it into the pot and cover it with the sliding lid。 The burning paper expels the air from the pot； and if it be perfectly tight you may raise the whole box by the lid。
VI。 GLASS FUNNELS。Are a necessary article to the Daguerreotypist； for filtering water； solutions； &c。 ＇hipho_14。gif＇
VII。 GILDING STAND。For nervous persons the gilding stand is a useful article。 It is adjusted to a perfect level by thumb screws placed in its base。
VIII。 SPIRIT LAMPS。The most useful and economical of those made are the Britania； as they are less liable to break； and the tube for the wick being fastened to the body by a screw renders it less liable to get out of order or explode。 Glass is the cheapest； and for an amateur will do very well； but for a professed artist the Britania should always be obtained。
IX。 COLOR BOX。These are generally found on sale at the shops； and usually contain eight colors； four brushes and a gold cup。 The artist would； however； do well to obtain； all the colors mentioned in the last chapter of this work； and be sure to get the very best； as there are various qualities of the same color； particularly carmine； which is very expensive； and the cupidity of some may induce them to sell a poor article for the sake of larger profits。 ＇hipho_15。gif＇
STILL。Daguerreotypists should always use distilled water for solutions； and washing the plate； as common water holds various substances in solution which detract very materially from the excellence of a photograph； and often gives much trouble； quite unaccountable to many。 For the purpose of distilling water the apparatus represented at Fig。 16 is both convenient and economical。
It may be either wholly of good stout tin； or of sheet iron tinned on the inside； and may be used over a common fire； or on a stove。 A is the body； which may be made to hold from one to four gallons of water； which is introduced at the opening b； which is then stopped by a cork。 The tube d connects the neck a of the still with the worm tub； or refrigerator B； at e； which is kept filled with cold water by means of the funnel c； and drawn off as fast as it becomes warm by the cock f。 The distilled water is condensed in the wormand passes off at the cock b； under which a bottle； or other vessel； should be placed to receive it。 The different joints are rendered tight by lute； or in its absence； some stiff paste spread upon a piece of linen and wrapped around them will answer very well； an addition of sealing wax over all will make them doubly secure。 ＇hipho_16。gif＇
HYGROMETER。This is an instrument never to be found； I believe； in the rooms of our operators； although it would be of much use to them； for ascertaining the quantity of moisture floating about the room； and as it is necessary to have the atmosphere as dry as possible to prevent an undue absorption of this watery vapor by the iodine &c。； and to procure good pictures；its detection becomes a matter of importance。 Mason's hygrometer； manufactured by Mr。 Roach and sold by Mr。 Anthony； 205 Broadway； New York is the best in use。
It consists of two thermometre tubes placed； side by side； on a metalic scale； which is graduated equally to both tubes。 The bulb of one of these tubes communicates； by means of a net…work of cotton； with a glass reservoir of water attached to the back of the scale。 Fig。 17 and 18 represent a front and back view of this instrument。
Fig。 17 is the front view； showing the tubes with their respective scales； the bulb b being covered with the network of cotton communicating with the reservoir c fig。 18； at d。 ＇hipho_17。gif＇ ＇hipho_18。gif＇ The evaporation of the water from this bulb decreases the temperature of the mercury in the tube b in proportion to the dryness of the atmosphere； and the number of degrees the tube b indicates below that of the other； shows the real state of the atmosphere in the room； for instance； if b stands at forty and a at sixty…one the room is in a state of extreme dryness； the difference of twenty…one degrees between the thermometerslet a stand at any one pointgives this result。 If they do not differ； or there is only four or five degrees variation； the atmosphere of the room is very moist and means should be taken to expel the superfluous quantity。
HEAD RESTS。The button head rest with chair back clip； A fig。 19is much the best for travelling artists； as it can be taken apart； into several pieces and closely packed； is easily and firmly fixed to the back of a chair by the clamp and screw a and b； and is readily adjusted to the head； as the buttons c； c and arms d； d are movable。
Sometimes the button rest is fixed to a pole； which is screwed to the chair； but this method is not so secure and solid as the clip and occupies more room in packing。 Both the pole and clip； are furnished in some cases with brass band rests instead of the button； but the only recommendation these can possibly possess in the eyes of any artist； is their cheapness。 ＇hipho_19。gif＇
For a Daguerreotypist permanently located the independent iron head…rest； B fig。 19； is the most preferable； principally on account of its solidit