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SCIENTIFIC NEWS. 



[Dec. 7, iE 



small spherical balls, more or less polygonal in outline 

 in section, with a faintly radiated crystalline structure 

 These spheres are seen to have been afterwards en- 

 veloped in the silica of the magma, as they have a 

 glistening pearly grey coating, resembling that known as 

 pearl-sinter or pearlite, which has been found in volcanic 

 tuffs from various parts of the world, although apparently 

 not previously recorded from Scottish volcanic rocks of 

 carboniferous age. 



Liverpool Science Students' Association. — At the 

 meeting on November 16th, a short but interesting 

 paper on " Instinct in Plants " was read by Mr. R. H. 

 Day. A paper on " The Philosophy of Cross-fertilisa- 

 tion," a subject of great interest to botanists, was read 

 by Mr. J. W. Baylis. The wonderful variety of flowers 

 in form, colour, and odour was graphically pourtrayed, 

 evidencing that they were factors in the production of 

 cross-fertilisation, which consisted in the fertilisation ol 

 the ovaries of flowers by pollen from other flowers of 

 the same species, effected through the agency of the wind 

 or insects. The conveyance of pollen is essential in the 

 great majority of plants, the sexes in some cases being 

 borne on separate flowers, and even when the male and 

 female organs are united in an individual, self-fertilisation 

 is made difficult or impossible by various causes, such as 

 the relative positions of the organs and the different 

 periods at which they arrive at maturity. The curious 

 contrivances and modifications that flowers, especially 

 orchids, possessed for the furtherance of cross-fertilisa- 

 tion, and the inter-dependence of flowers and insects in 

 the struggle for existence, were alluded to at consider- 

 able length. In closing, the essayist referred to the 

 researches in this direction of the late Charles Darwin, 

 and said the theory of natural selection was alone ade- 

 quate to explain the phenomena. An interesting discus- 

 sion followed, many members taking part, after which Mr. 

 W. Read exhibited in the lantern some interesting slides 

 illustrative of the coal measures of the Wigan coal field. 



St. John's Natural Science Society. — At the meeting 

 of this Society on November 27th, a lecture was delivered 

 by Mr. J. W. Slater, F.E.S., on "Nature's Sanitary 

 Service." The lecture was illustrated with specimens 

 of the insects most active in removing putrescent or 

 morbid matter. 



Falmouth Naturalists' Society. — At the meeting held 

 on November 26th, the Rev. A. R. Egar (President) in 

 the chair, the Rev. J. A. Leakey gave a lecture on " The 

 Antiquities of St. Gerrans." 



FLINTS* 



PROFESSOR J. W. JUDD said he must commence 

 by apologizing for slightly altering the order in 

 which he treated the subject that he had to bring before 

 them, owing to some alterations necessary in the micro- 

 scope-lantern not being completed. He would, therefore, 

 that evening proceed to speak of the modes of occurrence 

 of flints, leaving the microscopic treatment of flints for the 

 next lecture, when he hoped to be provided with the neces- 

 sary apparatus. In the remarks he had addressed to 

 them in previous lectures he had endeavoured to point 

 out what could be found out concerning flints by 

 means of expeiiments. Experiments, as they would 

 have perceived, were simply ways of observing how 

 Nature acted, but in experiments they, as it were, laid a 

 trap for Nature. They determined the conditions them- 



* Third Lecture to Working Men at the Royal School of Mines. 



selves under which Nature should act, and then watched 

 the process she followed. But the geologist was often 

 quite unable to follow out that mode of inquiry by 

 experiment. Often it was not possible for him to lay 

 down conditions under which Nature should act. He 

 could only take advantage of the circumstances, and 

 observe what took place under various conditions. Then 

 they spoke of that mode of inquiry as " observation." 

 They would see that "observation" and "experiment" 

 agreed in the fact that in both cases they were observing 

 the action of Nature, but in experiment they themselves 

 determined the conditions under which Nature acted, 

 whereas in ordinary observations they were obliged to 

 take advantage of any opportunities that were afforded 

 them of seeing how Nature worked. The object of ex- 

 periments and observations was to obtain a number of 

 facts upon which they could reason, and the reasoning 

 which they founded upon these facts and observations 

 was called inductive reasoning. When they had ob- 

 tained a sufficient number of facts and observations they 

 might form a theory — it might be but a working theory 

 — to account for the facts that they had observed, 

 and they might then proceed to try that theory 

 by other facts, and if it held, to extend and elabo- 

 rate the theory; or if they found that the theory 

 would not hold good, to give it up. That was the pro- 

 cess which was continually carried on in scientific work, 

 and he was going to ask them that night to inquire what 

 " observation " taught them concerning flints, what facts 

 they were able to learn from certain flints which would 

 enable them to make scientific inductions concerning the 

 mode of origin of those flints. 



They would inquire what was the mode and occur- 

 rence of flints ; in other words, where did they come 

 from ? Now every Londoner knew that there were 

 two sources from which flints were obtained. Some- 

 times flints were observed having a beautiful out- 

 side coating with a grey or black interior, which was 

 exhibited on fracture. They were all familiar with 

 ordinary white flints with black interior as being em- 

 ployed so commonly in rockeries, and sometimes very 

 ingeniously at railway stations, to pick out the names of 

 the railway stations in large letters. They were all fami- 

 liar with those large flints ; very irregular they were in 

 form ; and generally those large flints were obtained from 

 the chalk. They were got out of the chalk beds and were 

 brought to the places where they were used in the way 

 he had described, and in many other ways. But they 

 were equally familiar with another kind of occurrence of 

 flints. They saw flints which had not that black or grey 

 colour, and which have not white coatings outside. The 

 flints may be black or grey, but they were not unfre- 

 quently brownish, or reddish, or yellowish in colour, 

 and they were very different in appearance, and they 

 were without irregular and fantastic forms that they 

 were acquainted with in the flints from chalk beds. 

 These flints had various forms. Sometimes they 

 were almost perfectly angular; at other times the edges 

 were worn off and rounded. They were spoken of as sub- 

 angular flints. In other cases a mass had been worn into 

 a perfectly rounded form, a form called a pebble. Between 

 those several forms they found every possible gradation. 

 They might find flints which were evidently produced by 

 fracture and fracture only. The edges were perfectly 

 sharp and well defined. They might find others in which 

 the process of wearing down had gone on but a little 

 way, and the flint was thus sub-angular ; and others in 



