246 



SCIENCE-GOSSIP. 



modifications in the way in which it is filled up. 

 These variations are chiefly effected by altering the 

 friction at the pen-point by means of small weights 

 which are added or removed from the pen-holder. 

 This method, of course, affects the four repre- 

 sentative vibrations simultaneously ; but it is 

 possible to modify their rates of diminution of 

 amplitude either separately or in groups. 



The specimen figures here shown are chiefly of 

 the 3 : 1 ratio, corresponding to the interval of the 

 " perfect twelfth " — the most prolific of all the 

 ratios under ordinary conditions. 



Figs. 2 and 3 are strongly deflected specimens 

 showing compound change of phase ; a slow 

 change between the two ellipses, and a rapid 

 change in the deflecting ellipse. 



Figs. 1, 4 and 5 are super-posed figures, one 



figure being traced over another. In these cases 

 the deflecting movements are very faint, sometimes 

 scarcely perceptible. 



Fig. 6 is a unison, with varied rates of diminu- 

 endo, done with the main pendulum only. 



Fig. 7, a 5 : 2 ratio, corresponding to the " major 

 tenth." The deflection is very faint, a single figure 

 of one continuous line. 



Fig. 8, a 20 : 7 ratio counter-current, nearing the 

 3 : 1 ratio. It is discernible as a series of diminishing 

 squares, gradually revolving. 



All the principal outlines of twin - elliptic 

 curves may be found amongst the lathe-figures 

 known as " bi-circloids," but without any reference 

 to their geometrical constitution. 



(To be concluded next month.) 



THE DECOMPOSITION OF CARBON. 



^T J HEN chemists altered their notation about 

 thirty years ago, a very definite and precise 

 meaning was assigned to the term ' ' atomic weight 

 of an element," which was then placed upon a 

 simple and intelligible physical basis. Density of 

 the vapour of the different chemical substances 

 was taken as the guiding principle, and the atomic 

 weight of an element was defined as the smallest 

 number of units of weight of that element existing 

 in the standard volume of any compound contain- 

 ing that element. The smallest number of units of 

 weight of oxygen in the standard volume of the 

 vapour of any oxygen compound is sixteen, there- 

 fore the atomic weight of oxygen is sixteen. The 

 smallest number of units of w ; eight of chlorine in 

 the standard volume of the vapour of any chlorine- 

 compound is 35 - 5, therefore the atomic weight of 

 chlorine is 35"5- There are many compounds of 

 oxygen and many compounds of chlorine in which 

 the weight of the oxygen exceeds sixteen in the 

 standard volume, and the weight of the chlorine 

 exceeds 35 - 5, but in all these cases the weights are 

 multiples of sixteen or 35 - 5 respectively. It is 

 recognised that if any chemist were to find any 

 compound of oxygen wherein there was less than 

 sixteen units of weight of oxygen in the standard 

 volume of the compound, he would be entided to 

 proclaim the decomposition of oxygen ; and if any 

 compound of oxygen could be found containing any 

 quantity of oxygen other than a multiple of sixteen 

 in the standard volume, then the atom of oxygen 

 would be decomposed. Now just such a task has 

 been accomplished in the case of that wonderful 

 organic element, carbon. For a generation it has 

 been recognised that the weight of the carbon- 

 atom is twelve. An almost countless multitude of 

 carbon-compounds is known to chemists, and until 

 a few months ago, in not one single instance had 



anything been recognised except twelve or twenty- 

 four, or some other multiple of twelve units of 

 weight of carbon in the standard volume. 



The announcement made by Professor Wanklyn 

 in the Chemical Section of the British Association, 

 at the recent meeting in Oxford, that seven carbon- 

 compounds had been discovered in Russian kero- 

 sene, wherein the carbon-atom is six, is in reality 

 a statement that the carbon-atoms have been 

 decomposed in the extraordinary mixture of liquids 

 forming kerosene. It appears that most laborious 

 fractionation of Russian kerosene has disclosed 

 the existence of twenty-five distinct liquids, of 

 which seven have been proved to be the so-called 

 half-carbon bodies. 



The reading of Professor "Wanklyn's communica- 

 tion provoked discussion and moved Professor 

 Odling to severe criticism, in reply to which, 

 Professor Wanklyn concluded with the observation 

 " That the atomic weight of carbon is six, is not 

 opposed to any known fact, and the recognition of 

 the true atomic weight of carbon will bring into 

 view a region of organic chemistry, which up to 

 the present time has been hidden from our sight." 

 In chemistry questions of words and names, and 

 questions of atomic weights and numbered atomic 

 combining power (styled atomicity) are pregnant 

 with an infinity of practical application. The new 

 liquids extracted from kerosene will find many 

 useful applications. Some of them have medicinal 

 virtues, others will find a field of usefulness 

 as scent-giving and flavouring materials. The 

 employment of them as illuminantsis so obvious that 

 it hardly calls for mention at all. But Wanklyn 

 and Cooper's work is by no means confined to petro- 

 leum ; it embraces the spirit industry, to which 

 it promises new intermediate alcohols, with a 

 train of derivatives almost numerically infinite. 



