XOVEMliER, 1911. 



KNOWLEDGE. 



441 



When P. tlorihiiiula var. isabcUina. with its eighteen and 

 nine c.hroniusomes. is crossed with /-". kcicensis seedHng form, 

 with its thirty-six and eighteen, the offspring resemble the seed- 

 parent (P. floribitnda var. isabcUina) both in external 

 characters and in number of chromosomes. By some 

 regulating process the sum of 9 (xl + lS (x) = 18 (2x1. Again 

 an analog)' is found in the Oenotheras, for Oe. lata (fourteen 

 and seven chromosomes), crossed with Oe.gigas (twenty-eight 

 and fourteen chromosomes), results in a hybrid with_ twenty- 

 one (2x1 chromosomes; according to Geerts, at meiosis the 

 seven homologous chromosomes derived from either parent 

 become paired, while the seven supernumerary unpaired 

 chromosomes disintegrate, and in this way the x number of 

 chromosomes in the hybrid is reduced to that of the parent 

 w'hich possesses the lowest number. 



MISCELLANEOUS I^'^PERS.— Miss Kershaw described 

 the ovule of Boiccnia spcctabilis, which agrees on the whole 

 with other genera of Cycads. The pollen chamber of 

 Boux'nia forms by the breaking down of a strand of 

 elongated cells, extending from the tip of the nucellus aliuost 

 to the megaspore. First a small cavity (upper chamber) 

 forms in the narrow apex of the nucellus, and this probably 

 accommodates the pollen when it enters the ovule. The 

 nucellar tissue below gradually breaks down, forming a larger 

 ca\ity (lower chamberl, into which the pollen grains pass from 

 the upper chamber. The upper and lower chambers 

 correspond in function with the lagenostome and plinth of 

 such fossil seeds as Coiinstoma, but are much less specialised 

 than the corresponding structures in the Lagenostomales. 



Mr. Home discussed " The Polyphyletic Origin of Cor- 

 naceae," giving the results of detailed study of the flower of 

 several genera of this order, together with comparative studv 

 of the effects brought about by progressive sterilisation and 

 reduction in the ovary of the Caprifoliaceae, Hamamelidaceae, 

 and Araliaceae. In the Caprifoliaceae every intermediate 

 stage may be found between ovaries of the Lcycesteria type 

 (double rows of ovules in each chamber) and uniovular ovaries 

 [Vibnniinn) ; progressive reduction trends to the uniovular 

 condition, but each genus pursues an independent course of 

 development towards this condition. In the Cornaceae. the 

 flowers possess certain resemblances, e.g., polypetaly and 

 epigyny, while the ovaries or loculi in some genera are 

 uniovular with terminal ovules, but they possess peculiarities 

 in (a) structure of ovarj' (Corniis) ; (6) vascular supplv of 

 ovary {Garrya) ; (c) vascular supply to ovule [Grisclinia) ; 

 ((f) form of ovule (Davidia) ; (c) structure of nucellus 

 {.Aitcuba^ ; and so on. It is suggested that these peculiarities 

 indicate different origins ; the general resemblances in 

 structure do not appear to be of any considerable value in 

 establishing close relationships in the order, but are to be 

 regarded as striking parallelisms brought about by the opera- 

 tion of similar evolutionary processes upon distantly related 

 forms. 



During the Portsmouth meeting, a semi-popular lecture was 

 delivered by Dr. F. Darwin on " The Balance Sheet of a 

 Plant ■" ; while one of the evening discourses was given by 

 Professor Seward, his subject being '" Links with the Past in 

 the Plant World." 



Two interesting Excursions were made by the Botany 

 Section, one to the New Forest to study especially the heath 

 vegetation, the other in a steam launch up Southampton 

 Water for the estuarine vegetation, and especially the Spartina 

 grasses. 



CHEMISTRY. 



By C. AiNswoRTH Mitchell, B.A. (Oxox.), F.I.C. 



NATURAL GAS IN GALICIA.— Dr. K. Feldmann, 

 writing in Petroleum (1911. VI. 2232), gives an interesting 

 account of the steps recently taken to utilise the natural gas 

 emitted from the borings for petroleum oil in the Bor\'slaw- 

 Tustanowice oil-fields. Until about two years ago this gas 

 was. for the most part, allowed to escape into the air, only a 

 small proportion being used for heating and power purposes 

 upon the spot. Recently, however, a pipe-line has been 



constructed for conveying the S'lperfluous gas to Drohobyc^, 

 a distance of o\er eight kilometres, where it is intended to 

 utilise it in the oil-refineries and for distribution in the town. 



The gas issuing from the borings is colourless, and has a 

 specific gravity of about 0-75 and an average heating capacity 

 of about 10.S35 calories per cubic metre. Two typical 

 samples from different borings contairu'd S-7 and S-8 per 

 cent, of heavy hydrocarbons ; 86- 5 and Sj ■ 1 per cent, of light 

 hydrocarbons : 1-0 and 1 ■ 7 per cent, of oxygen ; and 3 • 8 and 

 6-4 per cent, of nitrogen (corresponding to 5 and 8 percent, of 

 air) respectively. 



The various pipes conducting the gas from the different 

 borings come together at Kamilla. and it is intended to establish 

 a central power station at that point. Here the gas is freed from 

 moistm-e. and passes through an apparatus which records the 

 percentage of air, this precaution being taken to prevent an 

 explosive mixture (one containing over 10 per cent, of air) 

 being distributed. As the gas is poisonous a small addition of 

 mercaptan is also made at this stage, in order to render any 

 escape perceptible by its odour. 



The main pipe is constructed of steel tubes which have been 

 tested in the works up to a pressure of ten atmospheres, and 

 these are coated with a layer of jute surrounded within the 

 trench with tar and lead. The finished pipe line is tested up 

 to a pressure of four atmospheres, although the maximum 

 pressure at which the gas is driven through it does not exceed 

 1 • 8 atmospheres. 



BOLOGNA LUMINOUS STONES.— Lemery in his 

 "Treatise of Chymistry." published in 1720, in a section 

 upon the Boionian Stone, describes it as " a small gray stone, 

 weighty but soft, sulphureous, sparkling in many Places, of 

 the Largeness of a Walnut, whose Surface is not equal but 

 bunchy and protuberant and the opposite side is hollow. 

 Large Stones are only \aluable for their Rariety : for they are 

 not so good to make the Phosphorus, because commonly they 

 are opaceous ; the small ones are nmch better, they shine 

 more and ha\'e fewer Blemishes." According to Lemery the 

 nature of the phosphorescence was investigated by an Italian 

 who '■ did particularly apply himself to this Discovery, and he 

 made great Progress in it. But it does not appear that he did 

 communicate the same to any Body, so that the secret has 

 been buried with himself many years ago." 



Since the days of Lemery the phosphorescent stones of 

 Bologna have frequently been examined and it has been 

 shown that the luminous property depends upon the presence 

 of sulphides. 



In a recent issue of the Jouru. prakt. Cheiu. (1911. 

 LXXXIV. 305) an account is given of experiments made by 

 Messrs. V'anino and Zunibusch to ascertain the factors upon 

 which the luminosity depended. They found that good 

 specimens of the stones contained from twelve to thirty-three 

 per cent, of sulphur, and that the condition in which that 

 element was present had a pronounced effect upon the results. 



Thus stones containing only monosulphides were very 

 deficient in luminosity, whereas in highly phosphorescent 

 specimens there was a considerable amount of polysulphides 

 (up to 2-5 per cent.) A small addition of starch increased 

 the luminosity, but a larger proportion than about four per 

 cent, had the opposite effect. The length of exposure to day- 

 light required to induce the maximum phosphorescence varied 

 with the composition of the stone, those of more complex 

 character requiring a longer exposure, though they also 

 showed a correspondingly longer period of decay. 



The luminosity was not increased by confining the stone 

 in an atmosphere of chlorine or ammonia. It was reduced to 

 a marked extent by grinding the stone in a mortar, the colour 

 being simultaneously altered. Exposure to sunlight also 

 changed the colour, but it was not possible to trace any 

 connection between the luminosity of the stone and the speed 

 with which its colour altered. 



CHEMISTRY AT THE BRITISH ASSOCIATION.— 

 The address of the President of the section. Dr. Walker, 

 deals with the "Theories of Solutions." which have arises 

 upon the foundations laid by van t'Hoft'. A masterly outline in 



