ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 261 
Burning that every microscopist who ventures into the realms of photo- 
graphy will do his own printing, a few hints may prove useful. There 
can be no doubt of the beauty and perfection of a good, properly toned, 
and finished print upon albumenized paper. This is conceded. But 
comparatively few amateurs will ever succeed perfectly in the operation 
of sensitizing the paper and toning the print, whilst most of the “ ready 
sensitized ” papers on the market are an abomination and a snare. There- 
fore avoid this method of printing, unless prepared to do first class work. 
Passing by platinum as being both expensive and uncertain, except- 
ing in the hands of an expert (although its beauty and perfection cannof 
be too highly extolled), let us consider for a moment the decided claim of 
bromide paper, as being the best material for printing in our class of 
work. Using the smooth surface paper and developing with ferrous 
oxalate, we get a perfect print rendering the most delicate details with the 
crispness and clearness of a steel plate engraving, which indeed it most 
closely resembles in very many instances. The exposure is made by 
lamplight, so that one is entirely independent of time or weather, and 
the finished print is quite permanent ; as much so, it is reasonable 
to believe, as a carbon print. If the sheet be allowed to dry by 
itself, it will present the appearance of an ordinary plate engraving. 
If a polished surface be desired, all that is necessary will be to float the 
paper, print side down, upon a sheet of polished hard rubber ; to squeeze 
it into optical contact, removing all superfluous moisture, and when 
quite dry it will peel off the rubber plate with a beautful polished 
surface, greatly increasing the delicacy of detail in many subjects, 
especially diatoms. Most decidedly my preference is given to thi s form 
of printing. 
But there is another method which, at the risk of being laughed 
at, I am inclined to gently urge. 1 refer to the ferro-prussiate, or 
more commonly named “ blue prints.” This method of printing is 
tabooed in many instance, “ blue prints ” being rigorously proscribed 
in the albums of the Postal Photographic Club, but for all that it 
has decided advantages and merits for the work we are considering. 
It is cheap, as the paper may be purchased ready sensitized, at very 
trifling cost, and it requires no skill or experience in the using. It is 
merely necessary to expose to bright sunlight until sufficiently printed 
(a few experiments will determine this), and then to wash in several 
changes of water ; the result being a bright permanent blue print upon 
a clear white ground, with excellent detail, excepting in the most 
delicate structures. 
The negatives made with the “ Handy ” camera are of a convenient 
size for printing lantern-slides by contact. A print on glass is certainly 
the most perfect of any that possibly can be made, and the impor- 
tance of this method of demonstration has long since been conceded. 
Gelatin plates coated on thin glass with special slow emulsi ms are 
furnished by several makers, and microscopists can readily make their 
own lantern slides with a little expenditure of time and patience. 
On some Processes of Photomicrography.* — Dr. S. Capranica gives 
an account of the processes and apparatus which he employed to establish 
the results given in this Journal, 1888, p. 651. 
* Zeitschr. f. Wiss. Mikr., vi. (1889) pp. 1-18. 
