250 
transpiration of the leaves.. ‘Then death of the leaf-tissues occurs 
sooner or later after calcium chloride solution of a certain 
strength has reached them. An upward current of the liquid 
ever, continue for some time after the leaves have been 
killed, especially if a weak Sa is being used and if the 
“specimens are exposed to sunlig] 
Four strengths of calcium pe ide solution were tried, having 
specific gravities of 1:05, 11, 1-2, and 14,* the strongest of these 
representing a nearly saturated solution at 60° F.. The liquids 
were prepared with the aid of a hydrometer, and were filtered 
before u 
The best result as regards resistance to withering was obtained 
with the two stronger solutions (sp. gr. 14 and 1:2), the treat- 
ment being continued for a week with exposure to sunlight a 
some hours. e specimens treated in this way were in 
condition after being kept for six months, and showed only slight 
irling of a few of their leaves. 
Experiments with the weaker solutions were less successful, but 
were not sufficiently numerous or varied to prove that weak 
solutions are unsuitable. A branch of copper beech was treated 
with 1°05 solution for eleven days, and remained well preserved 
for a considerable time. After six months most of the leaves 
showed slight curling, though not saab to spoil the appearance 
of the specimen. One or two twigs of the common beech, 
similarly treated, were still less saree as the leaves showed 
ecided “crumpling after a few weeks. 
The length of time required for the treatment with a given 
strength of solution will depend partly on te ama of the air 
and the degree of illumination, and proba a great extent 
also on the nature of the specimen. Thus ae sun—or shade— 
character of the leaves and the season at which the same are 
cut are presumably among the he lege concerned. In view of 
the uncertainty attaching to the len of time required, “it is 
probably best to continue the Pacteot until waterlogging of 
the leaves is attained, or even rather longer. The waterlogged 
the leaves. Exposure to sunlight is also recommended, as it was 
found to give the leaves a brownish colour, similar to an autumn 
tint, thus making dyeing unnecessary, unless other tints are 
aig 
the case of the specimens treated with the two stronger 
Mita the treatment was continued for at least a day after 
waterlogging was observed. An exudation of auld appeared 
on the lower side of the leaves of these specimens a day or two 
after the treatment with calcium chloride had been ‘stopped. 
The twigs were therefore left a few days longer, then rinsed 1n 
*In the ease of the weaker of these solutions, the ge increased its 
concentration to some extent daring the experiment, as the vessels 
containing t were not covered, and evaporation took place. 
