88 
POPULA?. SCIENCE EEVIETV. 
Industrial Use of Laminaria digitata. — An application of this large and very 
abundant species of sea-weed has been suggested in a paper read before the 
last Pharmaceutical Conference by Mr. Edward Stanford. He states that 
the stems of the tangle-weed Laminaria digitata when thrown up on the 
shore of the Hebrides are several feet long, and about as thick as the wrist, 
and when properly burnt they are converted into an excellent porous char- 
coal. This charcoal resembles that produced from animal matters, and has 
excellent properties as a means of filtering water. It has the following 
composition : — Carbon 50, phosphate of lime 4, carbonate of lime 20, car- 
bonate of magnesia 6, silicic acid 5, alumina 2, sulphate of potass 5, chlorine 
and iodine 5. 
A New Vegetable Parasite is reported to have been discovered by Dr. 
Beigel, the discoverer of the so-called chignon-gregarine,” Pleurococcus 
Beigeli. The new species has been found by Dr. Beigel upon the ear, and 
like that of the hair belongs to the algae. It will be described in that trea- 
sury of scientific contributions the Nom Acta. 
The Botanical Society of Canada is about to resume the publication of its 
Annals.” Botanists desirous of subscribing to this periodical may do so by 
paying four shillings annually. All communications are to be addressed to 
Dr. Lawson, Dalhousie College, Halifax, Nova Scotia. 
The Laws of Botanical Nomenclature. — M. Alphonse de Candolle is en- 
gaged in the preparation of a new edition of his Lois de Nomenclature.” It 
will be published in English and German, the English being entrusted to 
Messrs. Lovell Keeve and Co. 
Collection of European Plants. — In the Journal of Botany for November, 
the editor announces that Dr. E. Rostan, San Germano Pignerol, intends to 
dispose of his duplicates of European plants at 20 francs per hundred (where 
not less than one hundred species are selected). Botanists who desire to 
see the catalogue of about 6,000 species of vascular plants may communicate 
with J. Boswell Syme, Esq., 70, Adelaide Road, Haverstock Hill, London, 
N.W. Dr. Rostan has in preparation a catalogue of about 2,000 cellular 
plants. 
What is a Weed?— Dr. Trimen, of St. Mary’s Hospital, joins issue with 
Dr. Seemann on this point. He thinks it is impossible to give, as Dr- 
Seemann has done, a botanical definition of a weed which shall be unim- 
peachable. He considers, rather, that a weed is simply a plant in the wronof 
place, selecting such examples as Ononis arvensis, Tussilago Farfara, and 
Euphrasia Odontites. He says they are, certainly weeds, and very trouble- 
some ones, and also, we must believe, in the absence of any kind of evidence 
to the contrary, natives of this country. Silene inflata, Stellaria media, and 
Veronica hederifolia, seem to stand in the same category. There is no diffi- 
culty in supposing that such species have become weeds since the origin of 
cultivation, and as a result of it ; that, in fact, the conditions set up by agri- 
culture and gardening have furnished numerous localities highly favourable 
to their growth. In fact, a plant is a weed only in virtue of its situation ; 
it may be an ornamental or even a useful plant in its place, but out of that 
place it becomes a weed. A Sunflower in a field of turnips is as much a 
weed as Brassica Napus in a flower-garden, but reverse their situations and 
the term is inapplicable to either. So when waste land, such as heath, is 
