receives its coating in four seconds, it will be found that a proper
proportionate coating cannot be preserved by adopting, a proportion
of time, but on the contrary, the time will diminish; for exposure
over the accelerator, as in the above example, if it be desired to coat
the plate with twice as much iodine as in the above example, the time
would be, over iodine thirty-two seconds, and over the accelerator
(to possess a proper proportion) from six to seven seconds.
Hence it is that many inexperienced operators, when wishing to vary
their usual manner of coating, fail in producing a favorable result.
They coat calculating a proportion of time when they should not.

Dry Quick, No. 2.--Bromide of Lime and Magnesia.--To one quart of hydrate
of lime add one quart of magnesia, and mix them well together; add bromine
same as in preparing bromide of lime; coat the same as over dry quick No. 1.
This combination produces very uniform results, and is worked with much
success by beginners.

Chloro-Bromide of Lime.--To the bromide of lime add chloride of bromine
until the mixture becomes a pale yellow color, resembling sulphur.
It should be shook well, and enough of the chloride of bromine added
to bring the compound to a deep blood red color.

Use.--Coat over the iodine to a pink color, and then over the above to a red,
or just changing the color. It should be remembered that accelerators
containing chlorine do not admit of a great change of color of coating
on the plate.

Iodide of Starch.--This mixture can be employed for coating over in
warm weather, and prevent the flashing resulting at high temperatures.
It may be used the same as the iodide alone.