140 
[J anuary, 
Progress in Science . 
red in parts where there is less of it. It will entirely overcome the red if suf- 
ficient time be given. If the blue be used before the magenta aniline, the 
selection of colour is reversed. The sections should be mounted in Canada 
balsam, softened with benzole, as the presence of the latter may be beneficial 
in preserving the magenta. Respecting section-cutting and preparing sections 
for dyeing. — To cut a thick leaf, place a bit of it between two pieces of potato 
or turnip, and tie with a string. Cuts may be made along the midrib, or across 
it, including a portion of leaf on either side, or through several veins. Fine 
shavings of wood may be used, or pieces rubbed down on bones. Sections of 
leaves may be decoloured for staining by placing for some time in alcohol ; 
but Labarraque’s solution of chlorinated soda is to be recommended for twelve 
or twenty hours after the alcohol. In twelve hours wood is generally bleached ; 
too long treatment will, however, cause it to fall in pieces. After removing 
from the bleaching solution wash through a period of twelve or eighteen hours 
in half a dozen waters, the third of which may be acidulated with about ten 
drops of nitric acid to the ounce, which acid must be washed out. Next put 
in alcohol, in which sections and also leaves may be kept indefinitely ready for 
dyeing. One week instead of forty-eight hours is frequently required to effeCt 
the decolouration of large leaves in chlorinated soda, even when they are cut 
into several pieces, which is advisable. Mr. L. R. Peet, of Baltimore, thinks 
better results are attained by commencing with a weak dye, say from one- 
twentieth to one-twelfth of a grain, and slowly increasing the strength of the 
dye at intervals of from one to three hours until the required hue is obtained. 
This process guards against too deep staining, and gives a finer tone to the 
leaves under the microscope. 
Engineering, Civil and Mechanical. — Bombay Docks . — The question of 
providing suitable wet docks for the Port of Bombay has for many years been 
under consideration by the Government in India. Perhaps one cause which 
has contributed, as much as anything else, to delay commencement on the 
work, has been the faCt that two rival schemes have been in existence, one of 
which had for its objeCt the location of the Docks on the Elphinstone Estate, 
and the other at Moody Bay. It having, however, now been determined that 
the advantages of the former site have the pre-eminence over those of the 
latter, it has been determined to construed; the Docks there from the designs of 
Mr. Thomas Ormiston, the Engineer to the Bombay Port Trust. Contracts 
for the masonry part of the work have been let to the firm of Messrs. Glover 
and Co., Contractors, of Bombay. The first stone of the Docks was laid by 
the Prince of Wales on the occasion of his visit to Bombay. Further 
particulars of this work will appear in some future number of the “ Quarterly 
Journal of Science.” 
Liverpool Landing-Stage , — It will be remembered that on the afternoon of 
the 28th of July, 1873, the great landing-stage at Liverpool was destroyed by 
fire, an occurrence which caused no little inconvenience to the passengers 
crossing the Mersey. The old stage consisted of iron pontoons, which sup- 
ported five large wrought-iron kelsons on box girders, about 20 feet apart, 
running longitudinally the whole length of the stage. Across these kelsons 
were placed pine beams the width of the stage, and varying in thickness from 
16 inches to 14 inches by 12 inches. Upon these beams was fastened the 
longitudinal pine deck, or planking, 6 inches by 4 inches, and crossing this 
again were greenheart sheathing planks, 6 inches by 2 inches. The whole of 
this was caulked and pitched, to make it independent of the action of the water 
and the weather. The new stage consists of the pontoons and large wrought- 
iron girders as before, but, in place of wooden beams, iron beams have been 
substituted through the entire length of the stage. The pine deck-planking has 
been replaced with greenheart, and greenheart sheathing, as before, completes 
the decks. The new wrought-iron deck-beams weigh nearly 1500 tons, and 
this fact alone will give some idea of the magnitude of the undertaking, which 
was successfully completed by Messrs. Brassey, who were the contractors for 
the work. 
