July 7, 1 88 1 ] 



NATURE 



213 



other and successively smaller clouds were formed directly under 

 the first, having symmetrical and concentric outlines therew ith, 

 while the central vertical axis, which might be conceived as 

 passing through the whole series, remained unchanged and fixed 

 in space. This central fixity, too, of them all continued, together 

 with the infinite smoothness of the outlines of all the smaller lower 

 strata of cloud, although the largest and uppermost one visible to us 

 began to put forth a variety of fringes of cirro- cum ulcus character ; 

 and, as tested by the spectroscope before .ninset, all the luwcr 

 smooth-rimmed clouds were remarkable for the large quantity of 

 watery vapour they contained, and held fast too, for no rain fell. 

 As sunset appro.nched every one was gazing at the strange pheno- 

 menon of a cloud-congeries of most portentous size and absolute 

 fixature above the trade-wind, probably also the anti-trade 

 region ; and after sunset the most gorgeous coloured illumina- 

 tions through all the ranges of !carlet-red, red, crimson-red, 

 ultra-red, and then dun-coloured and grey passed from member 

 to member of the series, distinguishing the various heights of its 

 strata one above the other ; while the greatness of the general 

 height was shown, even long after darkness had set in, by a 

 faint lunar-hke illumination of the northern outline of the v\hole. 

 But by ten o'clock that began to fail, and the system of super- 

 posed clouds was beginning to contract on its central axis, and 

 faded away, without leaving its place, before morning. 



In so far we had bten witnessing, though without any positive 

 light of its own, a vertical series of disks of cloudy matter, 

 extremely like the lower end of the successive, transveree, 

 di'cons arrangements seen in a gas vacuum-tube of large dimen- 

 sions, when the electric discharge from a powerful induction-coil 

 is parsing through it; and we were inevitably reminded thereby 

 that the cosmical electric theory of M. Gaston Plante (of 

 "secondary batteries or storage" fame) justifies an escape of 

 the earth's interior electricity from time to time into planetary 

 space, and more particularly to the sun. 



Was there, however, in this case any symptom of the sun 

 exciting, or calling for, any such discharge, and from this part 

 of the earth? 



I'he sun was undoubtedly in the Northern Tropic, and the 

 highest northern declination for the year had just been reached ; 

 but for a fortnight or more past the solar spot manifestations 

 had generally been v\eak, almost fading a^^ay. This I knew 

 well, having taken a picture of the sun-spots every day (Sundays 

 excepted) since I have been here. However, though the appear- 

 ances were as poor as they well could be on June 21, 22, and 23, 

 yet on Frid.ay, June 24, there was a little improvement, fome 

 new, though small symptoms appearing in either solar tropic. 

 On Saturday, June 25, these new features were confirmed and 

 slightly increased. But what were they on Sunday, June 26, 

 when the extraordinary cloud-arrangement was hanging so long 

 above Madeira ? 



I, who am here merely as a private amateur in a different sub- 

 ject, know not ; but on Monday morning, so early as 5h. 30m. 

 a.m., I was astonished and delighted at the solar scene then pre- 

 sented. The spots fir>t caught sight of on Friday were now well 

 advanced and much developed ; a new group with extensive 

 double ramifications had also appeared in the same tropic nearer 

 the equator ; while finally, near the middle of the sun's disk in 

 the south tropic, were two large spots, with connections extend- 

 ing over 60,000 miles in length of solar surface, and indicating 

 more solar energy to have been thereby rapidly, if not suddenly, 

 manile^ted within the last forty hours, than anything which I, at 

 least, have witnessed for a very long lime past. 



PiAZZi Smyth, 

 Astronomer-Royal for Scotland 



Jones's Hotel, Quinka do Corvalho, 

 Funchal, Madeira, June 27 



P.S. — The grand, and now circumpolar, comet was not 

 neglected here on the same night. — P. S. 



Carbonic Acid Gas not Free in Sea Water 

 In a short paragraph in Natuee, vol. xxiv. p. 176, it is 

 stated that Torno, in the Norwegian Deep-Sea Expedition, had 

 found " carbonic acid both in a gaseous and basic form." 



For some time past I have doubted whether there was any 

 free carbonic acid gas in the deep water where pressure 

 should make its prefence felt. Lately, in a paper to the Royal 

 Microscopical Society, I have demonstrated that if there is any 

 carbonic acid in the sea water at great depths, its dissolving action 

 is not equal in rapidity and intensity to that exercised by a 



microscopic Thallophyte which bores into an bis-rVes sponge 

 spicules from within. Moreover amongst dee'' sea deposits I 

 find perfect organism; which have long been \vt'^. vl.ich have 

 been penetrated by parasites and covered !-,c ■: and there by 

 foraminifer.T, and yet in exposed parts, the ori.amentation is 

 perfect. There is no evidence of erosion. 



Now on carefully examining into Torno's essay come to a 

 different conclusion to the writer in Nature, and I 1 ud that the 

 able Scandinavian denies the existence of free carbonic acid in 

 the sea. 



The following notes, which I made in abstracting Torno's 

 "Chemi ' of the Norwegian North Atlantic Expedition, Part 

 II., ni.iy be interesting : — 



The carbonic acid gas, driven off by the process of boiling sea 

 water, when collected, varied in a most marked manner ; it was 

 always ai jireciable, and the quantity was sometimes large. The 

 pressure was that of the atmosphere. Under different conditions, 

 and when the gases were boiled out in a vacuum created by 

 tteam, and of course at a lower temperature, the quantity of 

 carbonic acid gas was often immeasurably small. Moreover the 

 quantity varied. 



Jacobsen, by distillation, succeeded in expelling the whole 

 amount of carbonic acid contained in a quarter litre of sea water, 

 and found that North Sea water contained 100 mgr. per litre. 

 The neutral carbonates in the re-iduary deposit contained about 

 10 mgr. per litre. Hence a very small proportion of the car- 

 bonic acid driven off by distillation, could have been present in 

 bicarbo!)ates. Vierlhaler had asserted that the carbonic acid in 

 sea water was got out of the bicarbonates by boiling. 



If tlic carlionic acid is free and absorbed by the sea water in a 

 free gas;ous form, it is remarkable that it should not be more 

 readily got. Jacobsen supposed that sea water has a pecnliar 

 properly of retaining its carbonic acid, owing to the presence 

 of the chloride of magnesia. Kuchanan was led to believe 

 that most of the salts were in son;e degree distinguished by 

 the properly of determining the retention of carbonic acid in 

 the sea. He especially insisted on the importance of the sul- 

 phates, and asserted the me: n amount of carbonic acid present 

 in the waters of the Southern Seas to be 43 '25 mgr. per litre. 



Torno, following Jacobsen, found the amount of carbonic 

 acid gas present in the water of Ihe track of the norlhern cruise 

 of 1877 to lie about 100 mgr. a litre, but gi t 12 mgr. per litre as 

 a variation in the amount. 



He was struck with the improliability that sea water should 

 possess so remarkable a pow-er of retaining mechanically one 

 gas and exert no corresponding influence on others, and then he 

 found that sea water had an alkaline reaction. He began to 

 believe that some of the neutral carbonates hod been decomposed 

 during the boiling, and had evolved much of the carbonic acid 

 gas. 



He then proved by experiment that the saline mixture in sea 

 water, on the temperature being raised to the boiling point, de- 

 composed neutral carbonates, and that all previous experiments 

 wi'li the object of mea-uring the carbonic acid in the sea water 

 had been faulty. He was influenced by some experiments on 

 the determination of carbonic acid gas in mineral water, and 

 applied the method to sea water. 



He found the total amount of carbonic acid gas in a specimen 

 to be 97 mgr. per litre, and the proportion forming neutral 

 carbonates to average about 53 mgr. The difference, 44 mgr., 

 cannot occur free as gas, but will unite with the carbonates to 

 form bicarbonates. Hence Jacobsen's experiments could be 

 explained on the assumption that sea water contains no trace of 

 free carbonic acid, but as much as 53 mgr. per litre forming 

 carbonates, and only 44 mgr. forming bicarbonates. 



On page 35 he states : "I/we bear in mind that sea water is 

 an alkaline Jitiid which does not contain Ihe smallest trace of free 

 carbonic acid." 



What a comfort this must be to globigerina and coral reefs ! 



June 27 P. Martin Duncan 



Symbolical Logic 



I am afraid I share the proverbial obtuseness of my country- 

 men in Ihe matter of jokes. I really did not at first see the 

 paint of Mr. Venn's humorous suggestion that "an attitude of 

 slight social repression " should be observed towards troublesome 

 authors of new proposals. Now however that Mr. Venn has 

 kmdly pointed it out to me (see Nature, vol. xxiv. p. 140), I 

 see the joke perfectly and can laugh at it heartily. 



