Sept. 29, 1 881] 



NATURE 



509 



confined chiefly to two spots, where it is seen only to the south- 

 east ; imagine a round, straight hole bored through a stratum of 

 sand sufficiently adhesive for the sides to remain erect for a time, 

 and after this suppose that the sand begins to fall inwards, 

 creating a partial cjne around to the south-east side ; this is the 

 sort of progress that these two spots convey. As to magnitude, 

 the spots are scattered over an area of some 6000 milHons of square 

 miles ; while the collective area of the sp its themselves is about 

 630 millions of square mile^^, or, say, six times the area presented 

 by the earth to the ;un. Remembering thit of solar change " a 

 little goes a long way," so far as we are concerned, who shall 

 say that changes of this magnitude are inappreciable on the 

 earth, however ineffectual the instruments we can now command 

 may be able to measure them ? But was this sudden cliange 

 imppreciable? that is now the question. Unhappily the sun re- 

 mained invisible till July 30, when two negatives were taken, i.e. 

 after an interval of just five days ; so far as solar rotation could 

 effect, the so-called new group of No should have been viible not 

 far from the sun's western edge ; but the entire grouphad vanished, 

 leaving no trace behind. In the interim of five days two new spots 

 had come out ; of one of these I may add that the umbra is 

 about 200 millions of square miles, and the penumbra some 700 

 millions, presenting in all a single feature of more than 900 

 millions of square miles, or say nine times the area exhibited by 

 the earth to a distant spectator. This ends the purport of my 

 letter. But I cannot help adding that I believe the bright solar 

 features or faculte will eventually prove to be more effective 

 exponents than the dark features or spots ; as a matter of fact, 

 facute commonly appear in abundance, covering considerable 

 areas and branching out from one another like coral reefs ; and 

 it ii a mistake to suppose that faculce exist only in the vicinity of 

 spots ; the former may abound where the latter are quite absent, 

 not only in a 4-inch negative, but in a very fair 5-inch equa 

 torijl. But I suppose the world will be better informed some 

 day. Meanwhile, siu'ely the sun is worthy of more earnest 

 attention, not only from piiiits of attack already so ab'y occu- 

 pied, but from others none the less important, though at present 

 greatly neglected : need I name solar radiation and photo- 

 graphy? Physicians are alarmed for the safety of our bodies on 

 detection of even a trifling chrnge in temperature ; but what do 

 we knou' of fluctuations in the source of all terrestrial heat, 

 though it be mea-^urable with an actinometer? Again, land 

 surveys are often made on hu^e scales; but for the solar survey 

 of \\ million millions of square miles, what is our largest deli lea- 

 tion, and at how many spots round the world is the required 

 daily record made? If a survey of London pays, depend on it 

 surveys of the sun will pay all nations infinitely better. 



J. B. N. Hennessey 

 India, North- West Provinces, Mussooree, August 5 



Proneomenia sluiteri, Hubrecht 

 In the report of the Proceedings of the Biological .Section of 

 the Briti'-h Association which appeared in Nature, vol. xxiv. 

 p. 501, there is a slight mistake in the notice of my friend Dr. 

 Hubrecht's paper on Proneomenia. This interesting mollusc is 

 erroneously described as "one of the valuable finds of the 

 Challenger Expedition." So far as I am aware, neither Proneomenia 

 nor either of the other two genera of the Solenogaslres (Neomenia, 

 ChiTloderma) was obtained by the C/ialleiiger. The only two 

 specimens of Proneomenia which are known to science as yet 

 were dredged by the Dutch Arctic Expedition of 187S (or 1879), 

 at depths of no and 160 fathoms in the Barents Sea. It was 

 not obtained by the Wilhelin Barents in iSSo, but we may hope 

 that the dredgings of thi< season have been more productive, for 

 Dr. Hubrecht informs me that 1S81 has be^n a very bad ice 

 year, and that the Wilhelm Barents has not succeeded in pene- 

 trating so far north as she has donj in previous years. The 

 summer has therefore been devoted to dredging operations, and 

 valuable results may be expected. The zoological results of the 

 Dutch Arctic Expeditions of 1878 and 1879 are being published 

 as supplemental volumes of the Niedtrliindische Arehiv fiir 

 Zoologie ; and in the second of these, which is now in course of 

 publication, will be found an elaborate memoir by Dr. Hubrecht 

 entitled '^Proneomenia sluiteri, gen. et sp.n., with Remarks 

 upon the Anatomy and Histology of the Amphineura." 



Eton College, September 24 P. Herbert Carpenter 



Polydonia frondosa 



The Medusa mentioned by Mr. Archer in NATURE, vol. 

 xxiv. p. 307, is undoubtedly Polydonia frondosa, Ag., figured 



ill the Contributions to the Natural History of the United 

 States. This Medusa was already known to Pallas, who de- 

 scribed a'coholic specimens sent him from the West Indies by 

 Drury. It is stated by Agassiz to be quite common along the 

 Florida K^ys. I have myself ob erved it in great abundance at 

 the Tortugas, in the moat of Fort Jeffer-on, and in the mud flats 

 to the north of Key West. They occur there in from three to 

 six feet of water, the disk res'.ing upon the bottom, the tentacles 

 turned upw ards ; the disk pmlsites slowly while they are at rest. 

 Their habits when disturbed are well described by Mr. Archer. 

 The young sometimes swim near the surface, and are far more 

 active than larger specimens. When kept in confinement they 

 also creep slowly over the ground by means of their tentacles, or, 

 raising themsrlves sometimes edgeways again-t the sides of the 

 dishes, remain stationary for a considerable time. The resem- 

 blance of Polydonia whei at rest upon the bottom to large 

 Actinia: with fringed tentacular lobes, such as Phythactis, is very 

 striking. The peculiar habits of Polydonia were noticed by 

 Mertens in a species named by Brandt P. A/ertensii in 1838; 

 and found at the Carolines. The genus Polydonia was esta- 

 blished by Brandt, and not by Agassiz, as is stated by Haeckel 

 in his "System der Medusen." Alexander Agassiz 



Cambri Ige, Mass., August 27 



Constancy of Insects in Visiting Flowers 

 Mr. a. W. Bennett's paper (Nature, vol. xxiv. p. 501) 

 on the "Constancy of Insects in Visiting Flowers" recalls a 

 note I made at Cromer during the hot w eather of last July. On 

 the clitTs w est of that town, where flowers were very abundant 

 and of various col mrs, I carefully watched the movements of t. 

 small tortoisohell butterfly to ascertain what flowers it visited. 

 It was at first busy with bindweed ; then it left this for yellow 

 hedstrav ■ (Galinm verum), returning presently to bindweed. 

 Then it tried a thistle, which detained it some time, after which 

 it shifted to ragwort, and finally revisited bindweed. It seemed 

 equally busy with all these flowers, though so various in form 

 and c dour. My tortoiseshell was therefore less constant than 

 Mr. Bennett's, and its visits were successive, there being no 

 interludes on grass, leaf, tree-trunk, or ground. 



Homerton College, E. J. T. PoWELL 



[In Mr. Bennett's paper, p. 501, col. 2, line 31 from bottom, 

 for from read more.] 



Brewing in Japan 



Will you permit me to point out an error vliich has crept 

 into the report of my paper on "Browing in Japan" in li.st 

 week's Nature, p. 468. After mentioning the points in which 

 A'dji differs from malt, the report continues : — " Koji is pre- 

 pai'ed as follows : a mixture of steamed rice and water is allowed 

 to remain in shallow tubs at a low teuqierature (o°-5° C.) until 

 quite liquid; it is then heated," and so on. The following 

 alterations will make the account of the Japanese brewing pro- 

 cess correct: — " Sak,! (rice-beer) is prepared as follows: a 

 mixture of steamed rice, koJi, and water is allowed to remain in 

 shallow tubs at alow temperature (0° - 5° C. ) until quite liquid ; it 

 is then heated ...''. Not u.-ing malt as we do in our brew cries, 

 the Japanese have discovered for themselves a means of render- 

 ing the rice-grains diastatic with allowing the embryo to germi- 

 nate. This is effected by exposing the softened rice-grains to 

 the action of dry steam, by which treatment the starch is gelati- 

 nised ; w hen cold the spores of a mould are cau-ed to grow over 

 the surface of the rice, the mycelium being formed at the 

 expense of the starch, and heat being liberated together with the 

 usual products of combustion. The albuminoid matter of the 

 rice, which previously was for the most part insoluble in water, 

 is, after the growth of the mycelium, found to be almost com- 

 pletely soluble, and the solution possesses diastatic properties 

 resembling tho;e of malt extract. The main point in which it 

 differs from the latter is in its superior hydrating power, for, 

 unlike malt-extract, the solution of idji very quickly converts 

 maltose into dextrose. This material (koji) is then used instead 

 of malt in the mashing process, the sugar fonned from the rice- 

 starch under the influence of the dissolved koji being dextrose, 

 which is further fermented by the accidental introduction froth 

 the atmosphere of the germs of a species of yeast. The change 

 induced in the character of the albuminoid matter under the 

 influence of the growing mould is remarkable, and, I think, 

 novel, and the interest of the observations I have made lies in 



