1887.] MICROSCOPICAL JOURNAL. 43 
There are innumerable formulas for toning-baths, but the simplest are the 
best. We give two. A stock solution of chloride of gold should first be pre- 
pared, which should have about two grains of the pute chloride to an ounce 
of water. The dealers sell what purports to be a ‘double chloride of gold 
and sodium ;’ in other words, a mixture of pure chloride of gold ie an 
equivalent of common salt. This is not an economical preparation to buy, 
and we should not be greatly surprised if this were partly due to the tempta- 
tion to sell salt at the price of gold. Ifthe pure chloride of gold cannot be 
obtained, it is advisable, if one is to do much toning, to prepare the chloride 
himself, for which instructions can easily be obtained from any druggist or 
chemist. 
Toning Bath No. 1. ‘ Toning Bath No. 2. 
Stock gold gomrign Ae I Oz. Stock gold solution, . . I Oz. 
Water.) : ety eT ONOZS. Watcoe ies WS Ee, a RT ONOZSs 
Baking soda, . Marek eke OLSEN. Acetate of soda, eee OOVST Ss 
The bath must be distinctly alkaline to litmus paper. If it becomes acid 
it will not tone. If toning proceeds slowly, and the reaction is distinctly alka- 
line, more gold should be added. 
No. 1 can be used immediately, and should be preserved, and more gold so- 
lution added when it is required for use. 
No. 2 works after standing twelve hours, and should also be kept, and gold 
added as required. 
Take the prints singly and put them into the toning bath, keep moving 
them about and turning them over. The reddish color will be observed to 
change to a brown and finally to a deep bluish color. Experience will be 
the only reliable guide here, so on the first trial of this operation take a sin- 
gle print, tone it Fate it seems to be done, then put it in the fixing solution 
given below, and observe the final color it assumes. In this way leave how 
far to carry the toning, and as the prints are toned one by one, put them in 
the vessel of clean water, to remain until all are toned. 
Fixing.—The toned prints are now transferred to the fixing solution, which 
is composed of hyposulphite of soda 1 part, water 4 parts, made distinctly 
alkaline with ammonia. The ammonia is not necessary, but it is a safeguard 
against any possible acidity of the solution, and seems to improve the tone 
of the pictures. About 20 minutes will complete the fixing. 
Final washing.—This should be very thorough. An abundance of water 
should be used, and frequently changed until every trace of hyposulphite is 
removed ; otherwise the prints will fade and turn yellow. 
Drying.—The prints may be spread out singly and allowed to dry, but 
if they are not to be mounted on cards it is better to let them partly dry and 
place them face to face between sheets of bibulous paper under moderate 
pressure until quite dry, when they will remain flat. 
Mounting.—This can best be done by a practical photographer , as a bur- 
nisher is required to finish the prints, and a good burnisher is a costly machine 
tobuy. If, however, it is desired to put ihe prints on cards, that may be 
done, and they may be sent to a photographer’s to be burnished. The prints 
are thrown into water, taken out singly, and made into a pile on a wetted 
glass plate, faces down. The superfluous water being removed by a cloth, 
the paste, which is sold by dealers but may be made of flour and water, is 
applied to the back of the uppermost print, and it is then picked up and ap- 
plied to the card. Considerable skill and practice are required to do this 
neatly. The paste must be just right, and it must be properly applied, and 
only experience will enable one to know when the work is properly pro- 
gressing. When it is all done, however, the burnisher has a habit of reveal- 
ing any imperfections, and it is likely to spoil improperly mounted prints, 
