I carry a light folding tripod which can be quickly and easily attached to or detached from the camera, as working in the dark with hands numbed from cold and wet, the simplest operation becomes a task, and the more simple the apparatus, the better the chance of success.
The lens I use is a Ross rapid symmetrical worked at full opening f8. Mr. Martin advises the use of a slow ortho chromatic plate, but considering the good quality of the fast plates as now made, and the great advantage gained by reduc ing the time of exposure, an advantage which one will appre ciate after a single trial, I very much prefer them, and results do not, in my opinion, suffer in the least from their use.
As halation must be guarded against, I adopted for this work the Seed non-halation plate, and back them as a further precaution.
Working on Mr. Martin's lines I at first included in the exposure a minute or two of the last departing daylight, if it might so be called, but my negatives approached too nearly daylight results, and I have since waited until night has really fallen before making the exposure.
Having chosen the view and set up the camera, if the only lights included are gas lamps the exposure with this lens and plate should be from eight to ten minutes, depending some what upon the distance to the nearest light, while, if any near electric lights are included, from two and one-half to three and one-half minutes will suffice.
When I speak of electric lights, I refer to those en closed in opal shades, such as are used on Fifth and upper Madison Avenue in our city. Unprotected lights or those enclosed in plain glass shades I have never attempted, and doubt very much if they can be successfully photo graphed.
My moonlight pictures were taken between io and o'clock, P. M., with moon almost full, and ten mintes' exposure.
During the exposure, a watch must be kept that no vehicle carrying lights crosses the field of view. My prac tice is to stand beside the camera, keeping one hand firmly on it, if it is blowing hard, several exposures I found were ruined through movement of the camera caused by the strong wind, then when a cab or other vehicle carrying a light enters the field of view, I, with the other hand, cover the lens until it has passed.
Moving objects not bearing lights make no impres sion on the plate.
In the development I aim at softness, and use a rather weak metol developer, two ounces stock solution diluted with water to four ounces, and with very little, say two drachms, alkali, no bromide.
The amount of detail picked up by the lens when using this plate, has been a constant source of wonder to me ; in every case, very much more than my eye could see was disclosed when the plate had been developed and fixed.
I prefer a stormy night for this work, either snow or rain, as the artistic effect is unques tionably much greater on these occasions." NITRATES.—Combinations of nitric acid with bases. For the most part they crystallize readily ; they are all soluble in water, and are generally neutral to test paper. The tests for nitrates are as follows : Solid nitrates, heated with copper and strong sulphuric acid, liberate red fumes. Liquids containing nitrates give the following reactions. Treated with an equal volume of strong sul phuric acid and allowed to cool, and then mixed with a fleshly prepared and clear solution of ferrous sulphate carefully added so as to float on the top, a brown ring will be observed at the junction of the two liquids.
If mixed with a little strong sulphuric acid, and then added to solid brucine, a red solution is produced.