412 



KNOWLEDGE & SCIENTIFIC NEWS. 



[April, 1906. 



is a circular compartment, including an historical legend 

 in bas relief of St. George and the Dragon. There is 

 also King Ptolemy and his Queen, with Sabra, their 

 beautiful daughter. On a thick rim is the ancient in- 

 scription : — " Ich Bart Geluk Aizeit; Bart Geluk 

 Alzeit." " I brought good luck always." 



The language is that of the Low Countries, which 

 marks it as being of Flemish manufacture; the form of 

 the lettering and the costume of the knight and his 

 palfrey points to an antiquity as remote as the be- 

 ginning of the 14th century. In the old almshouses 

 founded by Edward \T. at Saffron Walden is pre- 

 served an ancient and very valuable wassail-bowl of 

 brown wood with a silver rim, and a medallion in the 

 centre witli the \'irgin and child engraved on silver. 

 Its date is about 1400. 



A New Oxide of Carbon. 



By the action of the silent electric discharge on carbon 

 monoxide, Brodie, in 1873, obtained a reddish-brown 

 product which appeared to be an oxide of carbon; to 

 this product the formula C4 O,, or C., Oj was as- 

 signed, analysis giving somewhat variable numbers. 



Berthclot, in 1876, made similar observations and 

 found also that the brown amorphous product which he 

 obtained, gave, on heating, in addition to carbon mon- 

 oxide and dioxide, a dark coloured substance having 

 the composition CsO:,. 



With the exception of these somewhat indefinite pro- 

 ducts, which have since received but little attention, 

 chemists have up to the present time recognised only 

 the two well-known oxides of carbon — the monoxide 

 and dioxide. 



It is, therefore, a matter of considerable interest to 

 learn from Diels and Wolf (Ber. Deut. Cham. Ges. 

 February, 1906, 689), that they have isolated, in a 

 state of purity, a new and definite oxide of carbon 

 having the formula C3O0. It is prepared by the action 

 of phosphorus pentoxide in considerable excess on 

 malonic ester, the change being represented bv the 

 relation :— CH, (COOC, H,) , = 2CH, + 2H,0 + C, O, 

 This new oxide. — carbon sub-oxide, the authors term 

 it — is a colourless mobile liquid, which boils at 7° ; it 

 has an intensely pungent odour, somewhat resembling 

 that of acrolein or of mustard oils, and burns with a 

 sooty blue-edged flame. The composition was deter- 

 mined by combustion, and by explosion with oxygen 

 and the molecular weight by vapour density determina- 

 tion. 



When mixed with water, it dissolves immediately, 

 forming malonic acid, and ammonia in ethereal solution 

 converts it into malonamide. From these and other 

 properties and from its mode of formation, it may be 

 legarded as an anhvdride of malonic acid, and the 

 authors consider that its constitution is represented 

 by the formula O : C : C : C : O. 



By spontaneous decomposition, a dark-red amor- 

 phous substance is obtained, which dissolves in water, 

 giving an intensely red solution. 



H. J. H. Fentox. 



Erratum. — In the article by Mr. C. A. Mitchell last month 

 on Poisonous Plants used for catching fish, the expression 

 " natural order Derris " should be read as " genus," the 

 latter expression having been used by a slip of the pen. 



Thickness of the Earth's 

 Crust. 



By Frank Harris. 



The persistent survival of gross popular fallacies long 

 after their falsity has been clearly demonstrated, is one 

 of the most gloomy features in man's intellectual out- 

 look. 



.Some popular errors are, of course, much more 

 reasonably excusable than others; to imagine the earth 

 is fixed in space and devoid of motion is but to accord 

 unthinking belief to the immediate evidence of our 

 senses; and foolish only in that it fails to take into ac- 

 count the evidence presented by all except the most 

 violently striking of celestial phenomena. Far other- 

 wise is it with the popular belief that the earth con- 

 sists of a globe of molten matter enclo.sed in a solid 

 shell no thicker in proportion to its size than is the 

 shell of a hen's egg to its contents; and that assumption 

 of which this belief is the outcome, that the increase in 

 temperature noticeable on penetrating the earth to 

 trivial depths continues without limit towards the centre; 

 for, not only can the first supposition be e;i.sily proved 

 to be absolutely impossible, as can the fixity of the earth 

 in space, but also is there no excuse whatever for the 

 second assumption upon which the first is based; it is 

 an utterly illogical conclusion from our premises. 



If the earth contained anv masses of dense fluid 

 matter very great compared with the thickness of the 

 enclosing shell, that shell, even if constantly repaired, 

 would be utterly shattered twice in every twenty-four 

 hours by the moon's tide-compelling action on the f^uid 

 mass. 



If the earth had at any time consisted of a globe of 

 matter all at one temperature, say 7,000° F., and the 

 surface had been suddenly cooled down to its present 

 temperature and so maintained, in one thousand million 

 years the variation in temperature would be quite in- 

 sensible at depths exceeding five or six hundred miles; 

 and the variation near the surface— taking a reasonable 

 co-efficient of conductivity — would be in 100,000,000 

 years very nearly what is now actually observed. 



We need not, either, suppose the surface to be 

 suddenly cooled as in the abstract problem. Rock is 

 so poor a conductor of heat that as soon as the surface 

 was solid, a few thousand years — at most say one 

 million — would amply suffice to allow the actual surface 

 to cool down to a temperature so near that now existing 

 as to satisfy the supposed conditions. 



There is, therefore, no reason whatever for supposing 

 that the increase in temperature does not rapidly tend 

 to. a limit within a short distance of the earth's surface. 

 It is easy to form an approximate idea of what this 

 limiting temperature will be. 



Supposing, for simplicity, that the earth consisted 

 uniformly of granite; the limiting temperature would 

 be just below that at which granite solidifies under the 

 pressure to which it is there exposed. 



It makes no difference in essential principle whether 

 we suppose the earth originally to have consisted of a 

 globe of molten granite— as might result upon condensa- 

 tion from a nebula or upon adequate collision tetween 

 two approximately equal masses; or whether we suppose 

 it originally consisted of a solid nucleus surrounded by 



