+-------------------+--------------------+--------------+ | 1. | 2. | 3. | | 1 drachm of No. | 20 min. of No. 3., | A saturated | | 4., 6 drachms of | 6 drachms of | solution of | | distilled water. | distilled water. | gallic acid. | +-------------------+----------------+---+--------------+ | 4. | 5. | 6. | | 25 grains of | 2 drachms of | Equal parts of | | nitrate of silver | No. 4., 6 drs. | Nos. 1. and 2. | | to half an ounce | of water. | | | of water. Add 45 | | N.B.--This must | | minims of glacial | | be mixed just | | acetic acid. | | before using, | | | | and the bottle | | | | cleaned | | | | afterwards. | +-------------------+----------------+------------------+ _To excite for the Camera._--Mix equal parts of Nos. 1. and 2., and with a glass rod excite the iodized paper and blot off; and it may be put in the slide at once, or the number you require may be excited, and put into a blotting paper book, one between each leaf, and allowed to remain until required to be placed in the slide. _Time of Exposure._--The time varies from three minutes to a quarter of an hour, according to the nature of the subject and the power of the sun; but five minutes is _generally_ the proper time. _To bring out._--Bring out with No. 3., and when the subject begins to appear, add No. 5.; and when sufficiently developed hold it up, and pour water upon it; and then put it into hyposulphite of soda to fix it, for about half an hour {141} or more, and then into water: this is merely to fix it for the after process at your leisure. _To clean the Negative._--Get a zinc tray about three or four inches deep, with another tray to fit in at the top, about one inch deep; fill the lower tray with boiling water, so that the upper tray may touch the water; put your solution of hyposulphite of soda, not strong, in the upper tray, and then your negatives one by one, watching them with care until the iodine is removed; then put them in hot water, containing a small piece of common soda (the size of a nutmeg to about two quarts of water), for about ten minutes; pour off the dirty water, and then add more hot water, shaking them gently for a short time; pour off the water again, and then add fresh hot water, and let it remain until it is cold, after which take them out CAREFULLY, one by one, and put them in clean cold water for an hour or two; then take them _all out together_, and hold up to drain for a short time, and then put them between three or four thicknesses of linen, and press as much of the water out as you can; then _carefully_ (_for now all the size is removed_) lay them out flat upon linen to dry.