6j6 



NA TURE 



[April 25, 1889 



April 

 May 



38,000° C, and inconceivably attenuated as this interplanetary 

 atmosphere would be, the moon would yet come into con- 

 tact with 600 kilogrammes of it in each minute of time. 

 On a body like the earth, surrounded by an atmosphere, the 

 inevitable result of this unceasing collision with the inter- 

 planetary atmosphere would be the stripping away of the terres- 

 trial atmosphere layer by layer. Arriving at results of a similar 

 unacceptable character from the consideration of the action of a 

 •diffuse interplanetary gas on the other members of the solar 

 system, M. Hirn decides that matter exists only in a sporadic 

 state in space ; only in the state of distinct bodies —stars, 

 satellites, meteorites, and the like. It exists in a state of 

 extreme diffusion only in nebulae, but elsewhere space is perfectly 

 empty, or, at least, whatever remains cannot suffice to explain 

 the relations of stars to stars. 



Comets 1888 e and / (Barnard, September 2 and 

 October 30). — The following ephemerides for these objects are 

 in continuation of those given in Nature of April 4, p. 546, and 

 are for Berlin midnight : — 



Comet 1888/. 



R.A. Decl. 



h. m. s. o / 



9 31 10 ... 37 39-4 N. 

 9 33 48 ... 37 35"8 

 9 36 36 ... 37 30-4 

 9 39 38 ... 37 237 

 9 42 50 ... 37 15-8 

 9 46 12 ... 37 67 

 9 49 43 ••• 36 56-8 N. 

 reports from the Lick 

 Observatory that he has discovered this star to be a close 

 double. He gives the following measures of the companion : — 



Mag. 

 i889'i42 ... P = 327-0 ... D = 0-96 ... II 

 1889-151 ... = 325-9 ... = 0-83 ... II 



Mr. Burnham was not able to see the companion with the 12- 

 inch telescope, and concludes that it is too difficult for such an 

 aperture, the difference in magnitude between the two com- 

 ponents being so great. 



The White Spot on Saturn's Ring.— M. Terby, writing 

 to the Astronomische Nachrichten, reports that he has not been 

 able to see 'the white spot again which he observed on March 

 6 and 12 (Nature, vol. .xxxix. p. 497). MM. Knorre, Knopf, 

 Lamp, Struve, and Schiaparelli have likewise failed to detect it. 

 On the other hand, Prof. McLeod, of Montreal, and Mr. Brooks, 

 of Smith Observatory, Geneva, U.S.A., both state that they 

 have seen it ; and the latter reports it variable. If it be a real 

 spot, and not a mere effect of contrast with the shadow of the 

 planet, it evidently would only occasionally be seen in the place 

 where it was first discovered, but would be observed from time 

 to time in other parts of the ring, for it would be carried round 

 with it in its rotation. 



Comet 1888 



R.A. 

 h. m. s. 

 23 25 51 •• 

 23 23 34 ■• 

 23 20 54 .. 

 23 17 50 .. 

 23 14 18 .. 

 23 10 15 .. 

 23 5 37 •• 



24 



Urs/ic Majoris, 



Decl. 



I 28-1 N. ... 

 1 41-6 



1 54-1 



2 5-5 

 2 157 

 2 24-5 



2 31-6 N. ... 



Mr. Burnham 



ASTRONOMICAL PHENOMENA FOR 

 WEEK 1889 APRIL 2Z—MA V 4. 



(F' 



THE 



"OR the reckoning of time the civil day, commencing at 

 Greenwich mean midnight, counting the hours on to 24, 

 is here employed.) 



Ai Greenwich on April 28 

 Sunrises, 4h. 39m. ; souths, iih. 57m. 20-73. ; sets, igh. i6m. : 



right asc. on meridian, 2h. 23 •9m.; decl. 14° 18' N. Sidereal 



Time at Sunset, 9h. 44m. 

 Moon (New on April 30, 2h.) rises, 4h. 36m. ; souths, 



loh. 54m. ; sets, I7h. 25m. : right asc. on meridian, 



ih. 20-3m. ; decl. 3° 3' N. 



Venus in conjunction with and 10° 15' north 



of the Moon. 

 Mercury in conjunction with and 5° 8' north 



of the Moon. 

 Venus in inferior conjunction with the Sun. 

 Mars in conjunction with and 4° 21' north 



of the Moon. 

 Mercury at least distance from the Sun. 

 Variable Stars. 



Indicates that the setting is that of the following morning. 



THE CORROSION AND FOULING OF STEEL 

 AND IRON SHIPS} 



'T'HE difficulty of obtaining adequate experimental data, and 

 the fact that nearly everyone who has worked at the subject 

 has had a composition of his own to bring before the public, has 

 so hampered and restrained the free discussion and interchange _ 

 of ideas on this most important question, that at the present 

 time we have made but scant progress beyond the point reached 

 twenty years ago, and my object in bringing this paper before 

 you is more to excite you to discussion, and to show you the 

 known facts of the case, than to tell you of any very new or 

 startling discoveries. 



Corrosion generally precedes fouling on exposed metal surfaces, 

 and it is therefore this portion of the subject that will be con- 

 sidered first, together with the means which have been taken 

 to prevent it and to protect the plates of our vessels from 

 decay. 



In a paper which I had the honour to bring before you two 

 years ago, I pointed out that in all processes of rusting carbonic 

 acid gas and moisture played an important part, the iron uniting 

 with the carbonic acid and oxygen of the water to form ferrous 

 carbonate whilst the hydrogen was set free, and that the ferrous 

 carbonate then took up oxygen dissolved in the water, or present 

 in the atmosphere as the case may be, and was decomposed into 

 ferric oxide (rust) and carbonic acid, which being liberated in 

 actual contact with the moist surface of the iron carried on the 

 process of " rusting. " 



This view of the case was confirmed by a paper read by Prof. 

 Crum Brown before the Iron and Steel Institute, at Edinburgh, 

 last autumn, and is generally accepted as the true explanation of 

 the corrosion taking place on iron or steel surfaces exposed to 

 moist air or fresh water ; but the rusting of the metal in sea 

 water has by many chemists been ascribed to a more complex 

 action, in which the salt present plays an important part by first 

 forming oxychloride of iron. 



This preliminary stage of corrosion in sea water is, I am in- 

 clined to think, a myth. When iron filings or turnings are 

 exposed to the action of sea water, hydrogen gas is evolved, and 

 ferrous oxide and carbonate are formed, and this changes, as in 

 air or fresh water, into ferric oxide, by taking up dissolved 

 oxygen present in the water. At no time have I been able to 



'A Paper read at the thirtieth session of the Institution of Naval 

 Architects, by Prof. V. B. Lewes, F.C.S., F.I.C., Royal Naval College 

 Associate, on April 12, 1889. 



