TRANSACTIONS OF THE SECTIONS. 45 
In the several papers which will be brought before this Section,—in the elucidation 
their authors will personally afford, and in the discussions which will take place on 
them,—lI look forward to rich accessions to our knowledge, and to pregnant and fertile 
suggestions which will afford us matter of fruitful meditation hereafter ; and I am very 
sure, that in the course of such discussion as may involve differences of opinion, that 
spirit of mutual and amicable concession which has always characterized the meetings 
of this Section will continue to prevail. 
On Colorifie Lichens. By J. Beprorp. 
The lichens specially referred to were those used in the manufacture of orchil and 
cudbear, The author stated that prior to the year 1838, all the lichens employed 
were such as grow upon rocks only. In that year, however, a new kind of lichen was 
introduced from Angola on the west coast of Africa, by Mr. F. R. Batalho, a Lisbon 
merchant, to whom much credit is due for the discovery of its properties and uses. 
The novelty consisted in its being a twee lichen, as previously all such had been found 
useless for this manufacture. 
In 1839 another tree lichen, possessing valuable colouring properties, was discovered 
by Mr. G. C. Bruce in Ecuador, South America, and brought into the market in 
1840, under the name of Lima Weed. 
Similar lichens are now imported from Loango, Benguela, Mozambique, and Mada- 
gascar, several of which are considered to be of equal or even of more value than the 
best quality of rock lichens, The result has been to reduce the market price of 
orchil weed from about £300 to £50 per ton; and now tree lichens form something 
like four-fifths of the total quantity consumed in the manufacture. 
The author exhibited illustrative specimens of rock lichens from the Canary and 
Cape de Verde Islands ; also from Madeira, the Azores, and Sweden, together with 
the tree lichens from the places above-mentioned. 
On the peculiar action of Mud and Water on Glass, as more especially 
illustrated by some Specimens of Gilass found in the Lake at Walton Hall, 
near Wakefield, the residence of Charles Waterton, Esq. By C. W. Bine- 
LEY, Ph.D., F.C.S. 
Along with several other articles lately found in the lake at Walton Hall, near 
Wakefield, the residence of Charles Waterton, Esq., were some specimens of glass, 
supposed to have been submerged in the lake ever since the hall was attacked by 
Oliver Cromwell’s soldiers, 
The interest those specimens possessed in a scientific point of view consisted in the 
remarkable appearance they presented after their submersion, possessing hues of 
colour rivalling those of the finest specimens of pearl shells, Some of the specimens 
are of a beautiful azure blue by direct light, and yellow by transmitted light; others 
of a fine green colour by reflected light, and red and pink by transmitted light ; 
whilst others again are of a red and deep orange colour by reflected light, and blue 
by transmitted light. 
On scraping the glass with a penknife, the coloured part was detached in minute 
scales, those exhibiting the red and orange rays of colour coming off easily, when green 
and bluish scales became disclosed to view, which were with more difficulty removed. 
The glass underneath appeared as if it had been ground, or subjected to the action of 
hydrofluoric acid. On analysis, the scales were found to consist of silicates of lime 
associated with iron, but no potash or soda; whereas the glass consisted of a silicate 
of potash, with a very slight trace of lime and iron. The glass appeared, therefore, 
to be an alkaline silicate, and much more fusible and more easily acted upon by dis- 
integrating agents than the glass now manufactured. The potash originally in it 
appeared, in the case of the detached scales, to have been replaced by lime and iron 
derived from the water. The mud in which they had been imbedded was found on 
analysis to contain a large quantity of organic matter, containing nitrogen, and water 
charged with sulphuretted hydrogen. No sulphur was found in any form, either in 
the glass or in the scales, Any hypothesis, then, of the colours observed owing their 
origin to the combination of sulphur with the bases in the glass, the author observed, 
was perfectly untenable, 
