February 20, 19 13] 



NATURE 



67i 



The numbers may perhaps indicate a slight effect, 

 but notliing like what I expected. iVIy conductivity 

 tests of the sea-water brought back by Mr. King from 

 Hudson's Strait in igio gave a value of 004S0 at 

 25° C. Correcting for temperature this observation 

 serves to connect the sea-water entering the Strait of 

 Belle Isle with that in Hudson's Strait. Eastward 

 from Belle Isle Strait the conductivity rises rapidly 

 for 180 miles, after which it becomes uniform up to 

 450 miles. The greatest arctic current sweeps down 

 close to the Labrador shore, and in through the Strait 

 of Belle Isle, where the resultant flow is westward. 

 The following measurements of the conductivity 

 through the ice track by the Belle Isle route were 

 obtained last October on the Empress oj Britain. The 

 values were all measured at a uniform temperature 

 of 2.::° C. 



etfect on the shape of the equipotential surfaces in 

 adjacent space. Dr. Simpson, in the letter referred to 

 by Mr. McLennan, mentions the real poser, viz. why 

 in spite of the vertical current the earth retains it's 

 negative charge in fine weather. C. Chree. 



Abeam of Belle Isle 



Fortv miles east of Belle Isle .. 



Eighty miles east of Belle Isle .. 



One hundred and sixty miles .. 



Two hundred miles 



Two hundred and sixty miles .. 



Four hundred miles 



Four hundred and fiftv ... 



. . . 004865 



. . . 0-04986 



... 0-05047 



..., 0-05150 



-•• 0-05235 



... 005257 



... 005211 



... 0-05257 



It is evident that the great arctic current is of a 

 lower order of salinity, and that its course may be 

 traced along our eastern coast. 



In the early spring when the water is cold the 

 Newfoundland fishermen will find the cod in the 

 vicinity of the icebergs, and will always obtain their 

 catch there. Perhaps this is an indication of the 

 warming influence of the bergs, for the cod will not 

 live in very cold water. 



Next summer I shall continue my observations more 

 particularly with reference to the influence of land 

 on the temperature of the sea. I hope before long 

 to be able to publish here some typical microthermo- 

 grams showing this effect. H. T. B.\rnes. 



McGill University, January 27. 



Atmospheric Potential. 



Under the above heading Mr. Evan McLennan 

 refers in Nature, February 13, p. 647, to supposed 

 puzzles in atmospheric electricity. That certain diffi- 

 culties exist no one can deny, but Mr. McLennan 's 

 difficulties might, 1 think, be removed by consultation 

 of existing text-books. The vertical current which he 

 thinks should exist in the atmosphere does exist, and 

 methods of measuring it with more or less accuracy 

 have been in operation for some years. Mr. C. T. R. 

 Wilson devised an apparatus for its direct measure- 

 ment, and his experiments, made in good weather 

 near ground level, gave a mean value of about 

 2xio~'° amperes per sq. cm. .\ mean value of the 

 same order, but slightly larger, has been deduced at 

 Potsdam from continuous observations of the electric 

 conductivity of the atmosphere and the potential 

 gradient. To get an electrical current through a ver- 

 tical conductor it is necessary to bring its upper end 

 to the potential of the surrounding atmosphere. 

 " St. Elmo's fire " is a well-known natural phenomenon. 

 Currents can be obtained through a wire attached 

 to a kite, but the experiment at times may be dan- 

 gerous. Mr. McLennan seems to suppose that the 

 potential in the free atmosphere increases uniformly 

 with the height. Observations, however, have shown 

 that the normal rate of increase of potential per 

 unit of height diminishes as the height increases and 

 becomes small at the height of a few kilometres. A 

 mountain, it should be remembered, is part of the 

 earth, and shares its potential; if steep it has a large 



NO. 2260, VOL. 90] 



The Ascent of the Italian Balloon "Albatross," 

 August 12, 1909. 



In N.wure of August ig, 1909, a note appeared 

 stating that in an ascent from Turin the Italian 

 balloon Albatross, manned by Lieut. Mina and Signer 

 Piacenza, had reached a height of 38,715 ft., which 

 is greater by about 3000 ft. than any authenticated 

 record for a manned balloon ascent. A communica- 

 tion has recently been received from Prof. Palazzo, 

 director of the Italian Meteorological Office, in which 

 he states that the aeronauts Mina and Piacenza were 

 not provided with the necessary instruments for 

 measuring the height which they reached, and that 

 M. Mina, in the Rivista Tecnica d'Aeronautica of 

 1910, modified his earlier estimate and sought to 

 prove that the balloon had reached a height of 

 9240 m. (30,300 ft.). Owing to the absence of a 

 proper record of pressure and temperature, however, 

 even that value is uncertain. W. N. Sh.^w. 



Meteorological Office, South Kensington, 

 London, S.W., Februarv 12. 



Induced Cell-reproduction in the Protozoa. 



The discovery of the fact that the products of cell 

 death can cause cell-division in lymphocytes and other 

 cells of the human body has given rise to a strong 

 suspicion that these substances may be necessary for 

 any form of cell-reproduction to occur. It has been 

 already demonstrated by Fantham and Ross that 

 Amoeba coli can be caused to divide through many 

 generations by means of auxetics, and Drs. Ross and 

 Cropper have shown that induced cell-reproduction 

 will occur in the ova of Ascaris megalocephala if the 

 eggs are mixed with a solution containing auxetics 

 and incubated. It is important, therefore, for con- 

 firmation to come from other sources. Some time 

 ago I was fortunate enough to discover a new variety 

 of Polytoma, differing considerably from P. uvella 

 in many respects, but chiefly in the fact that the new 

 variety formed spores in the late autumn, which did 

 not develop until the following spring. A full account 

 of the new organism is in course of preparation for 

 publication. 



These winter resting spores seemed to me to be ex- 

 tremely suitable objects for testing the action of auxetics. 

 Some preliminary experiments were accordingly made 

 to see whether increase of temperature would cause 

 development. Spores were placed under suitable con- 

 ditions in the incubator, and kept at a temperature 

 of 25° C. for periods varying from one to three weeks. 

 On careful examination it was found, however, that 

 no change had taken place. 



A solution was then prepared containing 2 c.c. of 

 a 4 per cent, solution of theobromine, 04 c.c. of a 

 5 per cent, solution of sodium bicarbonate, and 0-5 c.c. 

 of a I per cent, solution of atropine sulphate, and the 

 mixture diluted to 10 c.c. with water. Water con- 

 taining large quantities of tlie spores was then mixed 

 with an equal volume of this solution, and the mix- 

 ture was incubated at 25° C. On examination at the 

 end of forty-eight hours about 5 per cent, of the 

 spores were found to show indications of division, 

 while controls containing no auxetics .showed no 

 chanee. I then worked with a concentrated extract 

 of sheep's suprarenal gland, augmented by the addi- 

 tion of 0-5 c.c. of a I per cent, solution f radaverine 



