November, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



589 



Widened Lines in Sun-spot Spectra. 



Professor C. Michie Smith has recently issued another 

 circular, giving the lists of solar lines intensified or other- 

 wise affected in sun-spot spectra. The observations extend 

 from F to D, and cover the period 1905, July 5, to 1906, 

 January 4. Thirty-three spots were examined, and an 

 appendix shows the special points noted for several lines. — 

 (Kodaikanal Observatory BuUitin, No. 6.) 



Oxford University Observatory. 



In his report on the work of the University Observatory 

 for 1905-6, "Professor Turner states that the printing of the 

 Oxford portion of the Astrographic Catalogue was com- 

 menced at Christmas, and the first of the eight volumes is 

 nearly completed. 



The expedition to Assouan, Egypt, to observe the total solar 

 eclipse of August 30, 1906, was successfully carried out with 

 the assistance of Captain Lyons. Several satisfactory 

 photographs of the corona were taken with the astro- 

 graphic object glass, one being through a green-colour 

 screen. Pictures in polarised light were obtained with two 

 small telescopes. It is hoped to measure these plates at 

 the earliest opportunity. 



The event of the )ear was the meeting of the International 

 Union for Co-operation in Solar Research in Oxford, at the 

 New College. Delegates from the various scientific institu- 

 tions of the world attended and discussed the problems most 

 in need of attention at the oresent time. 



.^^^^^^ 



BOTANICAL. 



By G. Massee. 



Macroplancton of Paraguayan Ponds. 



Dr. Cuod.\t, in liuU. Herb. Buissicr, distinguishes between 

 Microplancton and Macroplancton, including in the former 

 all microscopic organisms, and in the latter the larger free 

 floating plants belonging to the Archegoniatcs and Sperma- 

 tophytcs, including species of iS'tiiDuita, Utricularia, Lcinna, 

 cVc. Among remarkable species occurring in Paraguay arc 

 I'tricularia iiiilata, common in swamps, having the in- 

 Horescence supported by verticillate leaves arranged in hori- 

 zontal bands, cut into shreds at the extremities, and inflated 

 at the centre. I'lujllanthus Auitans, a curious plant belong- 

 ing to the Euphorbiacea;, which simulates a Salvinia, occurs 

 floating amongst species of Salvinia, AzoHa, and Lemna. 

 The leaves are almost orbicular, and float on the surface of 

 the water. A broad, flat margin encircles two more or less 

 dome-shaped elevations, one situated on each side of the 

 mid-rib on the upper surface of the leaf. Two depressions 

 on the under surface of the leaf, corresponding in position 

 to the domes on its upper surface, are filled with imprisoned 

 air, and serve as buoys to float the plant. The minute 

 flowers are situated in the axils of the leaves. The stem 

 produces numerous much-branched, positively geotropic root 

 fibres devoid of root-hairs, and terminated by a short 

 adherent cap. Another interesting swamp plant, Altvr- 

 nanihcra HassJeriana, has a floating stem which attains a 

 length of 20 cm., the internodes are cigar-shaped or spindle- 

 shaped, hollow, and when young are covered with a dense 

 coat of interwoven hairs. A quantity of air imprisoned in 

 this felt assists in enabling the plant to float. Tufts of erect 

 leaves, also the flowers, spring from the nodes. The roots 

 spread outwards in two tufts from opposite sides of the 

 nodes, thus preserving the equilibrium of the floating struc- 

 ture. 



Anthoceros and its Nostoc Colonies. 



The assoiialiiin of colunius of Xufliir and other allietl 

 forms of minute blue-green alg:c with certain of the more 

 highly organised plants has long been known, and has led 

 to much speculation as to the significance of such unions, 

 but uiilil quite recently no specific experiments have been 



instituted with the object of arriving at a more definite 

 conclusion. Peirce has just described, in the Botanical 

 Gazette, a series of experiments and cultures bearing on this 

 subject, where Anthoceros, one of the liverworts, which has 

 been supposed to habitually contain colonies of Nostoc in its 

 thallus or vegetative portion. Minute filaments of the alga 

 enter the substance of the liverv»ort through certain slits 

 present in the surface of the thallus, and afterwards increase 

 rapidlv and form colonies in the substance of the thallus. 

 Prantl has stated that Anthoceros derives benefit from the 

 presence of Nostoc, assuming that the latter might fix the 

 free nitrogen of the air, and contribute its products to the 

 liverwort. He also points out that the liverwort forms free 

 hairs, which penetrate into the Nostoc colonies present in 

 its tissues, ostensibly for the purpose of absorbing the food- 

 supply furnished by the Nostoc. Finally the thallus cavities 

 containing the alga show a characteristic development. 

 Peirce combats these statements as follows : — Anthoceros 

 grown as pure cultures and quite devoid of Nostoc colonies 

 proved to be more vigorous in every respect than others 

 containing colonies of the alga, and, furthermore, many of 

 the liverworts not grown as pure cultures, were also free 

 from Nostoc. As to the statement that the blue-green algje 

 fix free nitrogen, it is pointed out that the weight of evi- 

 dence is against this assumption. It is also shown that the 

 structural peculiarities presented by Anthoceros when Nostoc 

 is present are simply a matter of mechanics. The denser 

 tissues surrounding a colony is due to pressure exercised by 

 the constant increase in size of the colony on the surround- 

 ing tissues, and the ingrowth of hair-like structures into 

 the Nostoc colony is due to the fact that the colony is not 

 equally dense and resistent at all points of its surface, and 

 hair-like outgrowths of the surrounding Anthoceros cells 

 grow into the alien colony at the points of least resistance. 

 Zanczewske, on the other hand, considers the algal 

 colonies as parasitic on the liverwort. This idea, however, 

 is not supported by Peirce's experiments, although he is 

 not prepared to state definitely that no parasitism exists, but 

 concludes by stating that Nostoc certainly does not benefit 

 Aiitlioccros, which, in fact, does better without it. 



CHEMICAL. 



By C. .\iNswoRTH Mitchell, B.A. (0.\on.), F.I.C. 



The Sacred Water of Mecca. 



.V RliCENT issue of the Lantct gave the results of an analysis 

 of water taken not long ago from the Zem-Zem well at 

 .Mecca, and it is interesting to compare the figures with 

 those obtained by the present writer in the examination of 

 the water brought back, in 1S54, b}' Sir Richard Burton 

 from his celebrated pilgrimage (see " Knowledge," 1S94, 

 vol. XVII., p. 56). The recent sample of the water was con- 

 tained in a soldered tin bottle, in which was also a rusty- 

 looking sediment, which proved to be iroii hydroxide. The 

 water, which Burton obtained at the risk of his life, was 

 also sealed up in tin bottles of a peculiar shape, but in that 

 case the t)nly insoluble matter was in the form of beautiful 

 silken crystals containing tin derived from the interior of 

 the flask, and there was no iron present. 



The Lancet's sample contained 200.2 grains of solid matter 

 per gallon, 49.7 grains of chlorine, and 0.28 grain of 

 nitrogen in the form of nitrates. The residue when heated 

 gave olT a sickening odour and turned black. The writer in 

 the Lancet points out that the water contains about go times 

 as much free ammonia as is present in ordinary water, and 

 remarks that " to call it polluted would be mere euphemism." 

 This fully bears out the present writer's conclusion, and is 

 not surprising when it is remembered that for generations 

 this water has been poured over myriads of pilgrims, who 

 drank what they could as it ran down them and back 

 through a grating into the well. Hence, the water has 

 become little better than sewage eftluent. That brought 

 home by Burton contained 219 grains of solid matter, 69.3 

 ;;rains of chlorine, 19.9 grains of nitrates, 5.3 grains of 



