294 



SCIENCE-GOSSIP. 



show much greater tendency to ascend than do the 

 lower ones ; and the ultimate branching seems, as 

 has been alread) T stated, to follow three main types. 

 In the more luxuriant, robust, and rapid -growing 

 examples a horizontal fanlike form, a pendulous 

 one in the slender-growing varieties, and a gnarled 

 or zigzag in the more fioriferous and in the slow- 

 growing and less vigorous specimens of the tree. 

 It is of this latter that Gilpin remarks : "It par- 

 takes so much of the oak that, when it is rough and 

 old, it ma3 r easily, at a little distance, be mistaken 

 for one." Whilst contrasting the loose growth of 

 the wych elm with that of the small-leaved elm, he 

 truly says of the former : " It is perhaps generally 

 more picturesque than the common sort (i.e. U. 

 campestris), at least on a foreground, as it hangs 

 more negligently ; though at the same time with 

 this negligence it loses in a good degree that happy 

 surface for catching masses of light which we 

 admire in the common elm and which adapts it 

 better to a distance." 



1 7: \: ::Kl : .Kki.i. 



OSCILLATORIA IN HOT WATER. 



A TANK in this town receives daily the boiling 

 waste water from the engine-house of a large 

 factory, but has time to cool to a normal state of 68 

 degrees, Fah., before the next inlet; it then reaches 

 105 degrees, Fah. The water is also often charged 

 with a large amount of grease, and a dense scum or 

 algae grows in it. A week or so since I was asked 

 to examine some of this growth. At first I doubted 

 much if it was algae, because, instead of being a very 

 light clear green, as is the case with almost if not 

 all the algae, this, in mass, was so vein,- dark as to 

 be quite an invisible green, and the individual frond 

 or filament appeared purple under a one-inch 

 objective. Moreover, I failed to discover any 

 division into segments or cells containing zoospores, 

 or any sign of conjugation, budding, or germs 

 characteristic of algae and indispensable to life. 

 I tried, for a long time in vain, to find some mature 

 fronds, till I found what I thought might be its 

 usual mode of increase, viz., multiplication by 

 division. By what natural force or law r I could not 

 tell, but the two ends of a filament, originally in 

 line, were brought together showing remarkable 

 flexibility, they were then tightened by twisting 

 to such an extent that the filament snapped in the 

 centre, as a brittle stick would do under such a 

 strain. The twisting was repeated again and again, 

 but the filament did not always snap, nor did the 

 twisting always begin at both ends, more frequently, 

 perhaps, at one only. It was very curious to 

 watch the end jerking about like the nervous 

 twitching of a rat's tail. My first impression from 

 its rapid motion was that it was B miliaria parade xa 

 or something allied to it, though it had not the 



interesting gliding motion of that diatom, nor its 

 prettily marked frustules. Neither could I satisfy 

 myself that the movement was not due to the 

 numerous monads swarming round it. 



I increased my magnifying power to more than 

 1,000 diameters with advantage, having added fresh 

 water. The colour was now bright green, the 

 purple being apparently due to the grease. I then 

 saw that the twisting was its own inherent motion, 

 and never did I see bell-hanger twist a wire more 

 perfectly. I could also see what appeared to be 

 markings across the filament, and, by very close 

 scrutiny, that the apparent markings moved up and 

 down ; in fact that it was the circulation or 

 rotation of the endochrome. I noticed also that 

 this circulation always preceded the twisting, and 

 was in the same direction, and most probably the 

 cause of it. The diameter of a frond is as nearly 

 as possible the 5.000th part of an inch. Though I 

 placed the object on a flat glass with thin cover 

 glass over it, it was exceedingly difficult to keep in 

 the field of view long enough for another person to 

 see it, but I had the assurance of two witnesses as 

 to the circulation. "When my examination ended 

 I referred to Carpenter, and have no doubt about 

 identifying it with Oscillatoria. He notes the 

 continuous tubular filaments, and says the en- 

 dochrome which they contain usually exhibits 

 some degree of transverse striation, as if breaking 

 up into short segments, but this division is never 

 perfected, the fragments of endochrome, which are 

 to be regarded as gonidia, usually escaping from 

 their sheaths, and giving origin to new filaments. 

 The rhvthmical movement must be considered 

 simply as the expression of vital changes taking 

 place in the interior of the frond. F. Harrisson. 

 Cheadle, Staffordshire: January, 1896. 



Black Rain in Ireland. — About three summers 

 a°x> a very curious phenomenon occurred in a 

 district about six or eight miles in diameter, partly 

 in Tyrone and partly in Monaghan Count)'. One 

 day in the middle of summer the sky became so 

 dark and overcast that I wondered whether there 

 was an eclipse. In about an hour it became 

 lighter, but no rain fell in my neighbourhood 

 which was about ten miles away, But round 

 about Aughnacloy, and across from near Fintona 

 to Emyvale, black rain, very heavy, like a thunder 

 shower, overtook the country folk going to market. 

 The runnels by the road-side were flowing with the 

 dark liquid, and one farmer going to the water-butt 

 after the shower found the contents black, as if 

 someone had been washing an ink-bottle in it. 

 Clothes from the wash, drying on the hedges, were 

 deeply stained as if with sooty water ; and even 

 next dav when I was in the locality I noticed the 

 ruts in the road were of a dark colour. There is 

 no citv of considerable size whose smoke could be 

 precipitated from the air nearer than Belfast, some 

 fiftv miles awav. This, however, could not be the 

 cause, or it would be of frequent occurrence, one 

 would think, in England.— J^. F. de V. Katie, 

 Drumreask House, Monaghan, Ireland ; December, 1895. 



