80- 
Water sometimes complained, but that be never knew any man to be se- 
riously affected. He mentions, however, that in Kyanized timber an 
efflorescence of the sublimate has sometimes been observed, which might 
be injurious to cattle, if licked off from timber to which they have ac- 
cess. This might be prevented to some extent if the precaution used in 
Germany was adopted, of washing with hot water the surface of the 
timber when treated, and before being exposed. Mr. Bissell corrobo- 
rates the statements of Mr. Francis. He states that the man in charge 
of preparing the solution has, in a few instances, been nauseated for a 
short time by inhaling vapor arising from the solution ; but that he be- 
lieves this would have been prevented by a little more carefulness, and 
that the men handling the timber never suffered any injury, although 
frequently careless. 
The testing of a solution of the sublimate, as to its strength, can 
readily and accurately be performed. A graduated test tube being- 
filled with it, a solution of iodide of potassa is added, which precipi- 
tates the oxide of mercury as a red powder, which by the further ad- 
dition of the solution of iodide of potassa is again dissolved, so as to 
leave a clear liquid. The change in color can be accurately observed, 
and the numbers on the graduated test tube can be so arranged that 
the man in charge can read off the weight of bichloride of mercury to 
be added to bring the solution to its proper strength. 
There is ample testimony as to the efficiency of bichloride of mercury 
as a preservative of wood. The railroad ties of the Baden Kailroad, 
impregnated with it, lasted from twenty to thirty years. Mr. Francis 
states that in 1850 he put up a fence of Kyanized spruce lumber, which is 
still perfect, not a single piece having been removed during the thirty- 
five years, and only part of the wood which was under ground having 
decayed. The Pawtucket Street Bridge, built in 1849 of northern White 
Pine (Kyanized), did not require any repair until 1882, a period of thirty- 
three years. Kyanized timbers were used in nine spans of the Burr truss 
bridge, at Georgetown, which stood from 1810 to 1862, and failed, not 
from the decay of its timbers, but from bad construction. The Black- 
stone Kiver Bridge, on the New York and New England Kailroad, a 
Pratt truss built of Kyanized timber in 1818, when taken down in 1876, 
after twenty-eight years' service, was found but slightly decayed. Two 
bridges on the Philadelphia and Beading Bailroad, built in 1850 of 
Kyanized timber, proved sound after twenty years. 
The experience in this country as to Kyanized ties is not as favorable 
as in Baden. This may be due to two causes. On the Baden Bailroad 
the ties and all other timbers are air-dried during two or three weeks 
after impregnation and before being laid, which precaution is probably 
not observed in this country, and the road-bed in which the ties of the 
Baden Bailroad were laid consisted of a very dry gravel, which allowed 
all rain-water to run off at once. But even on other German roads the 
success of Kyanizing has been remarkable, and the failures which are 
recorded were due in many cases to imperfect impregnation. 
