TRANSACTIONS OF THE SECTIONS. 
77 
Dr. Martin Barry communicated the result of some observations 
on the colour of the sky, as seen from the summit of Mont Blanc; 
and expressed his conviction, that, while the depth of this colour 
appeared very much increased, as might be expected, from his ele¬ 
vated position, its peculiar tinge of black was in a great measure 
due to the contemporaneous reception by the eye of rays from the 
snow. He stated that the same effect has been observed by Boussin- 
gault in his attempted ascent of Chimborazo and other mountains. 
Cursory Remarks upon some matters contained in a Letter addressed 
by Mr, William Hamilton to Mr. Packenham. By William 
Schiede, M.JD. ( Translated by Mr. Hamilton.) 
1. The Oxalis tuberosa is a plant of Chili, not of Mexico; at 
least I have never heard of any plant of this genus with esculent 
roots being cultivated in the Mexican republic. The country 
abounds in wild species of Oxalis (the Xoxocayallin of Hernandez), 
some of which are applied to culinary purposes in the same manner 
as the Sorrels ( Rumex ) of Europe. 
2. The Solanum tuberosum is, without doubt, a native of this soil, 
as has been already published in the beginning of 1829. I have 
collected several varieties, which may, perhaps, prove to be distinct 
species. Moreover, I have collected among them one species (>Sb- 
lanum oxycarpum , Schiede) equally tuberous, and in every respect 
akin to the S. tuberosum , from which it differs in bearing pointed 
fruit. Notwithstanding which, the Papa, according to my researches, 
has no Aztec name, being known to the Aztecs by the name of 
Papa. Hernandez speaks of the Peruvian Papa ; which proves how 
> little he was aware of its being a plant of this country. 
3. According to my observations, the Cevadilla is a new plant 
( Veratrum officinale , Schiede). Hernandez has described and fi¬ 
gured it very indifferently under the name of Hzcuinpatli , or Dog- 
killer. It is a powerful anthelmintic, diuretic, antiarthritic, and an- 
tipsoric. I am not aware of its having been employed in the cure 
of hydrophobia. In the course of the last ten years a new species 
of Veratrum ( V. Orfilia , Sabadilla,) has been published by Des- 
courtilz, which he conjectures to be the plant which yields the ce¬ 
vadilla of the shops of Europe. In my opinion, this last plant is 
doubtful, and is at least distinct from the Cevadilla of this capital 
and of the shops of Berlin. 
4. I am not acquainted with the plant called Amole , of the pro¬ 
vince of Sonora. A root is exposed for sale in the market-place of 
Mexico, under the name of Amole , which is the Agave polyan- 
thoides of Schiede, or at least one nearly related to it. It is com¬ 
monly used for washing linen, in place of soap, as it abounds in an 
extractive and saponaceous principle. 
5. I do not know the Cestrum Mutisii. If I mistake not, it is a 
production of South America. In some parts of Mexico they em¬ 
ploy in its place the sap of the Justicia tinctoria ; but I cannot say 
