LKSSONS IN' <; Kit MAN. 



"77 



Tho Ions at the point A in fixed in tho circular tubo in front of 

 square draw-out tube, and ia of a focus equal to tho length 

 of tho box when tho drawer in half drawn out. A plain 

 mirrr, placed diagonally at an angle of 46, at the end of 

 tho box, aa shown by the dotted linos a b, reflects the rays 

 transmitted by the lens op to the upper side of tho plane 

 rough-ground glass, the rough side placed above, under tho fold- 

 ing darkening cover, and there forms the images of the objects 

 the lens at A. The uso of the drawer is to adjust tho 

 proper distance of the lena from the mirror, according to the 

 variable distances of proximate objects. The images on the 

 rough gloss exhibit a beautiful perspective picture, also the 

 profile of a person seated in a room in a strong light before the 

 camera, and more particularly if the sun illumines the object ; 

 and may bo readily traced on the rough surface of the glass by 

 a blockleod pencil, or by what is preferable, rod French chalk, 

 and then white paper being gently placed on the glass, the lines 

 will be correctly taken off. 



If very thin white paper is merely placed upon the glass, the 

 images may be discerned, though faintly, sufficient to afford the 

 moans of tracing correctly. The nearer the object or features 

 are to tho camera the larger will bo the image, and an additional 

 lens of a shorter focus is sometimes fitted, to be substituted for 

 the other when the images of very near objects are wanted. 

 " Some artists," says Recce (from whom the above description is 

 taken), " who copy profiles, remove the rough gloss from the cell, 

 invert the camera, and by a stand support it about ten or twelve 

 inches above the white paper on tho table. The imago will 

 then invertedly be formed on tho paper, and they trace it with a 

 pencil in a correct manner, and with less trouble than by the 

 other method." 



An improved folding camera is made by joining the side of 

 the camera and drawer in the middle with canvas cloth, as 

 shown at the line B G (Fig. 2) ; the back c turns inwards with tho 

 mirror, close up to the rough glass, and tho front E p above, over 

 the top, BO that tho whole camera may fold down into a flat 

 form, and go into a very portable, flat, leather strap case, 

 making it the most portable possible for persons travelling. 

 Inclusive of the rough glass, a double convex lens has some- 

 limes been placed to receive the images; and as more light 

 is then refracted, the images are shown with great beauty 

 and extraordinary brightness, even surpassing the original. 

 They are also more vivid when tho rough glass is placed above 

 this lens, though tho contours or outlines are not so sharp and 

 distinct as when the rough glass is used only by itself. This 

 arrangement was noticed by Hooper, in his " Rational Recrea- 

 tion," written one hundred years ago, and was subsequently 

 called "the Delineator," by Storer, who pretended to be tho 

 original inventor. 



The camera may be reversed, and used as a show-box for dis- 

 playing prints, etc. ; of course tho ground gloss must then bo 

 removed. Any boy, with a little care and dexterity, and at a 

 very small expense, may construct a camera out of an old hat ; 

 and as many hats are provided with ventilating holes at the 

 top, the aperture is ready for the insertion of the lens, and the 

 picture may be received upon a circular piece of tracing paper 

 stretched on a thin wooden hoop or frame, which may slide 

 backwards and forwards in the hat for the purpose of focussing 

 the picture. The lens must be of a sufficiently short focus to 

 suit the hat. This very simple arrangement will help the 

 youthful student to understand the phenomena of vision, as 

 tho whole may bo compared to the eye, and the oiled paper 

 upon which the picture ia painted will represent the expanded 

 nerve, the retina, or mind of the eye, upon which the pictures 

 ecen by this organ are projected. That such images are 

 projected on the retina is shown by using the eye of a sheep 

 or bullock, which may be readily procured from any butcher's 

 shop. If the back part of the eye is cut off so as to leave 

 the retina, and if the cornea of tho eye ifl substituted for the 

 lens in the hat, tho image of the external objects will be seen 

 painted upon the retina at the back of the cornea. 



As an amusing modification of the camera, and to shnw how 

 thoroughly the old experimentalists worked out an idea, and 

 applied it in various ways, may be instanced the next form. 



THE MAOIC TABLE CAMERA. 



A table, FFFF (Fig. 3), is provided with a top, A B CD, in which 

 a sheet of ground glass (E) is fitted ; below is the camera (M), with 



its lens in the tube, which may be thrust through a bole in the 

 wall of the room against which the table sUnds ; the image* 

 of the external object* are reflected from the mirror in the 

 lines N H o to the ground glass E. The picture () may be con- 

 cealed by a tablecloth, and when the room is darkened by 

 closing the shutters and the cloth removed, some wonder is 

 excited by seeing the images of external objects in all their 

 colours and with their natural movements delineated on the 

 table- top. 



A PHOTOGRAPHIC CAmtRA. 



In Fig. 4 is shown a more modern camera, such a one 

 as would be employed for taking photographic pictures t it 

 is called " a sliding body folding camera." It U usually 

 made of tho best Spanish mahogany, well seasoned, and brass- 

 bound, because the instrument is frequently exposed to the 

 direct rays of the sun, and if the wood cracked the light 

 might be admitted, which would spoil the prepared collodion 

 plate. When the picture intended to be taken has been f ocnsaed 

 on the ground glass at the back, the latter is removed, and an 

 ingeniously made box containing the prepared collodion plate 

 substituted for it. When all is ready, a sliding panel of wood 

 is drawn up, the prepared plate is then exposed to the light, 

 which is allowed to act for a certain time until the picture U 

 supposed to be obtained. The plate is afterwards developed 

 and fixed in the regular manner. The tube containing the 

 lenses is attached to a vertical and horizontal sliding frame, 

 in order to enable the photographic artist to adjust the fore- 

 ground and sky. 



LESSONS IN GERMAN. LIIL 



20. DECLENSION OP PROPER NOUNS. 

 Singular Number. 



(1.) Names of males and females, except when the latter ter- 

 minate in t, take t to form the genitive, which is their only 

 variation ; as : 



Nom. J&tinric^, Henry. 



Gen. Jjnnrid)*, of Henry. 



Dat. Jjcinrid), to Henry. 



Ace. JSfinru^, Henry. 



Glifafretfi. Elizabeth. 

 (flifabttb*, of Elizabeth. 

 Glifabetb, to Elizabeth. 

 Cltfabttt), Elizabeth. 



It is customary with some writers to affix en to the dative 

 and accusative of proper names ; but the better usage distin- 

 guishes these cases by prefixing tho article ; as, nom. Sefftng, 

 Lessing ; gen. Sefftng*, of Lessing ; dat. tern Sefftng (instead of 

 Seffina.cn), to Lessing; ace. ten Sefftng (instead of Sefftngen), 

 Lessing. 



(2.) Names of females ending in e form the genitive in en* 

 and the dative in en ; those of males ending in t, \(, f$, r, or * 

 take likewise in the genitive end; as -. 



Nom. Suife, Louisa. StibntB, Leibnitz. 9>c, Voss. 



Gen. Suifen, of Louisa. Set6ntfcen, of Leib- $cffcn, of Voss. 



mix. 



Dat. Suifen, to Louisa. SetbniB, to Leibnitz. i<c*. to Voss. 



Ace. Suife, Louisa. Seibnij, Leibnitz. $(*. Voss. 



(3.) Names, whether of males or females, when preceded by 

 an article, are indeclinable ; as : 



Nom. Der Skitter, the Schiller. 



Gen. De 3<f>iflfr, of the Schil- 

 ler. 



Dat. Dem filler, to the Schil- 

 ler. 



Ace. Den emitter, the Schiller. 



Die Strife, the Louisa. 

 Det Suife, of the Louisa. 



Det Suife, to tho louiaa. 

 Die Suife, the Louisa. 



21.- PROPER NOUNS IN THE PLURAL. 



(1.) Proper nouns, when employed in the plural, conform for 

 the most part to the rules for the declension of common nouns; 

 the masculines being varied according to the Old Declension, 

 and the feminities according to the New. 



Sometimes the plural is made by the addition of to tho sin- 

 gular ; as : Die <bi(Ier the Schillers ; tie ^trtert. the Herders. 

 Those ending in o add for the plural ne or nen ; as: (Sato. Cato; 

 nom. plnr. Oatcne or (Fatcnen, the Catos, etc. 



(2.) Their inflection is in no wise affected by the presence of 

 the article, nor do the radical vowels a, r, u. an, ever 

 the Umlaut. 



