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therefore not only a useless article； but very improper。 A bare floor is to be prefered； but if you must cover it use matting。 There is no place about your establishment where greater care should be taken to have order and cleanliness； for it will prevent many failures often attributed to other causes。 〃A place for every thing； and every thing in its place；〃 should be an absolute maxim with all artists。 Do not oblige the ladies； on going away from your rooms； to say〃That H。 is a slovenly man； see how my dress is ruined by sitting down in a chair that looked as if it had just come out of a porter house kitchen and had not been cleaned for six months。〃
In choosing your operating room； obtain one with a north…western aspect； if possible； and either with； or capable of having attached； a large skylight。 Good pictures may be taken without the sky…light； but not the most pleasing or effective。
A very important point to be observed； is to keep the camera perfectly free from dust。 The operator should be careful to see that the slightest particle be removed； for the act of inserting the plate…holder will set it in motion； if left； and cause those little black spots on the plate； by which an otherwise good picture is spoiled。 The camera should be so placed as to prevent the sun shining into the lenses。
In taking portraits； the conformation of the sitter should be minutely studied to enable you to place her or him in a position the most graceful and easy to be obtained。 The eyes should be fixed on some object a little above the camera； and to one sidebut never into； or on the instrument； as some direct； the latter generally gives a fixed； silly； staring； scowling or painful expression to the face。 Care should also be taken； that the hands and feet； in whatever position； are not too forward or back ward from the face when that is in good focus
If any large surface of white is present； such as the shirt front； or lady's handkerchief； a piece of dark cloth （a temporary bosom of nankeen is best；） may be put over it； but quickly withdrawn when the process is about two thirds finished。
A very pleasing effect is given to portraits； by introducing； behind the sitter； an engraving or other pictureif a painting； avoid those in which warm and glowing tints predominate。 The subject of these pictures may be applicable to the taste or occupation of the person whose portrait you are taking。 This adds much to the interest of the picture； which is otherwise frequently dull； cold and inanimate。
Mr。 J。 H。 Whitehurst of Richmond； Va。； has introduced a revolving background； which is set in motion during the operation； and produces a distinctness and boldness in the image not otherwise to be obtained。 The effect upon the background of the plate is equally pleasing； it having the appearance of a beautifully clouded sky。
In practising Photographic drawing on paper； the student must bear in mind that it is positively essential； to secure success in the various processes； to use the utmost precaution in spreading the solutions； and washes from the combination of which the sensitive surfaces result。 The same brush should always be used for the same solution； and never used for any other； and always washed in clean water after having been employed。 Any metalic mounting on the brushes should be avoided； as the metal precipitates the silver from its solution。 The brushes should be made of camels or badger's hair and sufficiently broad and large to cover the paper in two or three sweeps； for if small ones be employed； many strokes must be given； which leave corresponding streaks that will become visible when submitted to light； and spoil the picture。
These few preliminary hints and suggestions； will； I trust； be of some service to all who adopt this pleasing art as a profession； and will； with a due attention to the directions given in the practical working of the Daguerreotype； Calotype； etc。； ensure a corresponding measure of success。
CHAP。 V。
DAGUERREOTYPE APPARATUS。
The entire Daguerreotype process is comprised in seven distinct operations； viz：
1。Cleaning and polishing the plate。
2。Applying the sensitive coating。
3Submitting the plate to the action of light in the camera。
4。Bringing out the picture； in other words rendering it visible。
5。Fixing the image； or making it perminentso that the light may no longer act upon it。
6。Gilding： or covering the picture with a thin film of gold which not only protects it； but greatly improves its distinctness and tone of color。
7。Coloring the picture。
For these various operations the following articles which make up the entire apparatus of a Daguerrean artist must be procured
1。THE CAMERA。（Fig。 5。）。 The Camera Obscura of the Italian philosophers； although highly appreciated； on account of the magical character of the pictures it produced； remained little other than a scientific toy； until the discovery of M。 Daguerre。 The value of this instrument is now great； and the interest of the process which it so essentially aids； universally admitted。 A full description of it will therefore be interesting。 ＇hipho_5。gif＇
The camera is a dark box （a）； having a tube with lenses （b） placed in one end of it； through which the radiations from external objects pass； and form a diminished picture upon the ground glass （g） placed at the proper distance in the box to receive it； the cap c covering the lenses at b until the plate is ready to receive the image of the object to be copied。
Thus a （fig。 6。） representing the lens； and b the object desired to be represented； the rays （c； c） proceeding from it fall upon the lens； and are transmitted to a point； which varies with the curvature of the glass； where an inverted image （d） of b is very accurately formed。 At this point； termed the focus； the sensitive photographic material is placed for the purpose of obtaining the required picture。
The great disideratum in a photographic camera is perfect lenses。 They should be achromatic； and the utmost ＇hipho_6。gif＇ transparency should be obtained； and under the closest inspection of the glass not the slightest wavy appearance； or dark spot should be detected； and a curvature which as much as possible prevents spherical aberration should be secured。 The effect produced by this last defect is a convergence of perpendiculars； as for instance； two towers of any building； would be represented as leaning towards each other； and in a portrait the features would seem contracted； distorted and mingled together； so as to throw the picture out of drawing and make it look more like a caricature than a likeness。 If the lens be not achromatic； a chromatic aberration takes place； which produces an indistinct； hazy appearance around the edges of the picture； arising from the blending of the rays。
The diameter and focal length of a lens must depend in a great measure on the distance of the object； and also on the superficies of the plate or paper to be covered。 For portraits one of 1 1/2 inches diameter； and from 4 1/2 to 5 1/2 inches focus may be used； but for distant views； one from 2 inches to 3 inches diameter； and from 8 to 12 inches focal length will answer much better。 For single lenses； the aperture in front should be placed at a distance from it； corresponding to the diameter； and of a size not more than one third of the same。 A variety of movable diaphrams or caps； to cover the aperture in front； are very useful； as the intensity of the light may be modified by them and more or less distinctness and clearness of delineation obtained。 These caps alway come with Voitlander instruments and should be secured by the purchaser。
Though the single acromatic lens answers very well for copying engravings； taking views from nature or art； for portraits the double should always be used。 The extensive manufacture of the most approved cameras； both in Europe and in this country； obviates all necessity for any one attempting to construct one for their own use。 Lenses are now made so perfect by some artisans that； what is called the 〃quick working camera〃 will take a picture in one second； while the ordinary cameras require from eight to sixty。
The camera in most general use is that manufactured by Voitlander and Son of Germany。 Their small size consists of two seperate acromatic lenses； the first； or external one； has a free aperture of 1 1/2 inches； the second； or internal； 1 5/8 inches； and both have the same focus； viz： 5 3/4 inches。 The larger size differs from the smaller。 The inner lens is an achromatic 3 1/4 inches diameter； its focal length being 30 inches。 The outer lens is a meniscusthat is bounded by a concave and convex spherical surface which meethaving a focal length of 18 inches。 For every distant view； the aperture in front is contracted by a diaphram to 1/8 of an inch。 By this means the light is reflected with considerable intensity and the clearness and correctness of the pictures are truly surprising。
THE AMERICA instruments are constructed on the same principle and many of them are equally perfect。 Mr。 Edward Anthony of 205 Broadway； New York city； has constructed； and sold cameras fully equal to the German and for which Voitlander instruments have been refused in e