12 



NA TURE 



[May 4, 1893 



In the Annales of the French Meteorological Office, recently 

 published for the year 1890, M. Angot has discussed the 

 observations taken simultaneously during that year at the 

 Central Meteorological Office and on the Eiffel tower, and has 

 arrived at some interesting results respecting the variation with 

 height of the several meteorological elements. The reduced 

 barometric pressure was lower every month on the tower than 

 on the ground, the probable cause being the great difference in 

 the velocity of the wind at the two stations. The observations 

 made at the three stations on the tower allow of the variations 

 of temperature with altitude being studied with great detail, and 

 it was found that the rate of diminution was far from being pro- 

 portional to the height above the ground. In all months, at 

 the middle of the night-time, the temperature increased with 

 altitude, the maximum difference occurring at a mean height 

 of about 500 feet, it then decreased at first slowly, and after- 

 wards more rapidly; at about 1000 feet the mean rate of decrease 

 already amounted to i°'4per 100 metres (328 feet) During the 

 middle of the day-time the decrease of temperature with height 

 above 500 feet is nearly uniform in all months, being about l°-6 

 for each 100 metres. Between 500 feet and the ground, how- 

 ever, the decrease showed a marked annual variation ; during 

 the cold season the difference was less than that observed at the 

 higher level, while in the hot season it was much greater. The 

 diurnal variation of vapour tension at the summit of the tower 

 exhibited entirely different characteristics from those near the 

 ground ; generally speaking, there was only one maximum, 

 near noon, and one minimum, between the evening and mid- 

 night. During all months the vapour tension was less at the 

 top of the tower than near the ground. The diurnal variation 

 of the wind exhibited a marked minimum at the top of the 

 tower during the day-time, and a maximum at night, being the 

 reverse of what is observed at ground stations. 



The Board of Agriculture has issued a valuable report on 

 rust or mildew on wheat plants. It contains a complete 

 account of the life-history of the fungus of ordinary mildew, 

 Puccinia graminis, as well as of tliat of spring rust and mildew, 

 Ptucinia riihigo vera, with a discussion of tlie conditions 

 favourable for their propagation, and the best means of averting 

 them. It is illustrated by some excellent coloured plates by 

 Mr. Worthington Smith. 



Rather less than three years ago (Nature, vol. xlii. p. 297) 

 we had to record the death of Mr. W. K. Parker, and in doing 

 so we gave some account of the main facts of his career. An 

 excellent little biographical sketch of him by his son, T. Jeffrey 

 Parker, has just been published by Messrs. Macmillan and Co. 

 In an introductory letter Prof. Huxley speaks of the volume as 

 one which "gives a presentation as accurate as it is vivid, of a 

 man of noble and lovable character, endowed with intellectual 

 powers of a very unusual order." Prof. Huxley says he has 

 " never met with another such combination of minute accuracy 

 in observation and boundless memory for details, with a vagrancy 

 of imagination which absolutely rioted in the scenting out of 

 subtle and often far-fetched analogies. '' " The genius of an artist 

 struggled with that of a philosopher, and not unfrequently the 

 latter got the worst of the contest." 



At the instance of some Russian meteorologists, who have 

 frequent occasion to measure very low temperatures, M. 

 Chappuis lately undertook a study of the spirit thermometer 

 I^Arch. de Sciences). He traces its anomalies to three sources, 

 {l) Adhesion of the liquid to the walls of the capillary 

 tube. When the instrument is brought from ordinary tem- 

 perature to a lower, the sinking column leaves liquid on the 

 tube, which for hours, and even days, continues slowly descend- 

 ing. (2) Irregular expansion of the spirit with the temperature. 

 As the expansion increases with heating, the graduation should 

 NO. 1227. VOL. 48] 



be made to correspond, the degrees for higher temperature' 

 being longer (which is not usually the case). (3) Impurities in 

 'he spirit, and varying water-content, which affect expansion 

 materially. M. Chappuis recognises the difficulty of getting 

 rid of these faults, and concludes that alcohol is not to be recom- 

 mended as a liquid for thermometers marking low temperatures. 

 On the other hand, it has been shown that toluol (with a boiling 

 point of about i [o° C.) is a liquid well adapted for the purpose 

 and free from the disadvantages referred to. 



Lake Memphramagog— the Loch Lomond of Canada— lies 



partly in the State of Vermont, but belongs to the St. Lawrence 

 hydrographic system. It is thirty miles long, and varies from 

 one to four miles in breadth. It lies in the lap of high hills, 

 and is a deep-water lake, soundings in one locality indicating 

 depths, it is claimed, of 600 ft. Mr. A. T. Drummond writes 

 to us that from reading* taken on August 10 last, at II a.m., 

 under a strong sun and cloudless sky, two facts appear to be 

 established :— (l) that Lake Memphramagog is a cold-water 

 lake whose bottom temperatures are in August as low as 44°75 

 Fahr. ; (2) that the high surface temperature is only main- 

 tained for relatively a few feet, beneath which the mercury falls 

 rapidly towards the lowest reading. There is a decided surface 

 current at the southern end, arising from the inflowing streams 

 there, and it is suggestive the warm waters from these slieam^ 

 flow, river-like, over the colder waters of the lake, just 

 as the Gulf Stream, under a different influence, but lightly 

 skims the surface of such a large portion of the broad 

 Atlantic Ocean. Whilst the thermometer at twelve fathoms 

 registered 51", the waters of Lake Ontario, at their outlet 

 into the St. Lawrence indicated at the same depth, and at 

 about the same period, 67'. 



The green colour in certain oysters, localised in the gills and 

 palps, and lost under certain conditions, is known to be due to 

 an insoluble pigment introduced by a diatom on which the 

 oysters feed. It has been shown lately by M. Pelseneer, of 

 Ghent {Rev. Sci.), that a process of "phagocytosis" here 

 occurs. The pigmentary granulations are an injurious product 

 in the blood ; and they are devoured by the blood corpuscles, 

 which, thus charged, pass into the gills and palps, where the 

 blood is separated from the outer water by a mere thin layer of 

 epithelium. The corpuscles penetrate between the epithelia 

 cells, where some are destroyed, and some pass right through 

 and escape. It is thus explained how green oysters placed in 

 water without the diatom referred to lose their colour very 

 quickly (in thirty-six hours at most), the charged corpuscles 

 being rapidly eliminated. 



The success of the luminous fountains at the Paris Exhibition 

 of 1889 suggested to M. Trouve the idea of producing the 

 effects on a small scale and cheaply. Several forms of this 

 small fountain are described in the Bulletin de la Sociiti 

 d Eiicmnagement. Instead of illuminating the water jets by 

 lateral mirrors, M. Trouve lights up with an incandescent lamp 

 at the focus of a parabolic mirror a sort of inverted glass with 

 apertures for the liquid. M. Trouve also here describes his 

 method of imitating lightning at one of the Paris theatres. In- 

 stead of flashing lycopodium powder behind a broken line cut 

 in the scenery (the old plan), a long bamboo or other flexible 

 rod is used, having a small incandescent lamp of great brilliancy 

 at the end, with a foot commutator, enabling one to make or 

 break the circuit at will. The rod is moved quickly down in a 

 zigzag direction at the proper moment. The sound of the wind 

 in a storm is imitated by means of a double-action pump and 

 two sirens ; and that of hail by throwing coarse sand against 

 an osier screen. 



A SIMPLE optical photometer, serving also to measure the 

 degree of visual power, has been devised by Dr. Simonoff 



