One lens 6 or 7 focus
One lens telephoto or telecentric 9 to 12 focus

The camera should be made of metal and fitted with focal-plane shutter
and direct view-finder.

A sole leather case with shoulder-strap should contain the camera and
lenses, with an extra roll of films, all within instant reach, so that
a lens could be changed without any loss of time.

Plates, of course, are the best, but their weight and frailty, with
difficulty of handling, rule them out of the question. The roll film
is the best, as the film pack sticks together and the stubs pull off
in the moist, hot climate. The films should be purchased in rolls of
six exposures, each roll in a tin, the cover sealed with surgical
tape. Twelve of these tubes should be soldered in a tin box. In places
where the air is charged with moisture a roll of films should not be
left in a camera over twenty-four hours.

Tank development is best for the field. The tanks provided for
developing by the Kodak Company are best for fixing also. A nest of
tanks would be a convenience; one tank should be kept separate for the
fixing-bath. As suggested in the Kodak circular, for tropical
development a large-size tank can be used for holding the freezing
mixture of hypo. This same tank would become the fixing tank after
development. In the rainy season it is a difficult matter to dry
films. Development in the field, with washing water at 80 degrees F.,
is a patience-trying operation. It has occurred to me that a small
air-pump with a supply of chloride of calcium in small tubes might
solve the problem of preserving films in the tropics. The air-pump and
supply of chloride of calcium would not be as heavy or bulky as the
tanks and powders needed for development. By means of the air-pump the
films could be sealed in tin tubes free from moisture and kept thus
until arrival at home or at a city where the air was fairly dry and
cold water for washing could be had.

While I cordially agree with most of the views expressed by Mr. Fiala,
there are some as to which I disagree; for instance, we came very
strongly to the conclusion, in descending the Duvida, where bulk was
of great consequence, that the films should be in rolls of ten or
twelve exposures. I doubt whether the four-barrel gun would be
practical; but this is a matter of personal taste.

APPENDIX C.

My Letter of May 1 to General