124 SIMPLER ORGANIC SUBSTANCES 



J. L. Smith^'* succeeded in isolating a compound having the 

 composition C4HgS5 from the Orgeuil meteorite. Compounds 

 having the formula CgHgOa were found in the Orgeuil and 

 Hessle meteorites. The number of such finds increases from 

 year to year. 



At the time when the presence of hydrocarbons in meteor- 

 ites was first discovered people were, as we have already 

 indicated, still firmly convinced that, under natural condi- 

 tions, organic substances could only arise biogenically. It 

 was not unusual, therefore, for scientists to put forward the 

 hypothesis that the hydrocarbons of the meteorites had been 

 formed secondarily as the result of the decomposition of 

 organisms which had lived on them at some time. We have 

 shown, however, in Chapter II, that all the numerous 

 attempts to find microbes, their germs, or any other organised 

 remains, have been quite fruitless. On the contrary, all the 

 experts on meteorites, such as A. Fersman, F. Levinson- 

 Lessing, V. Vernadskii and others, agree that there is nothing 

 in meteorites which resembles a sedimentary formation or 

 which could, in general, suggest the possibility of the exist- 

 ence of biogenic processes. It follows that the hydrocarbons 

 of the meteorites, like those of the cosmic dust, arose abio- 

 genically, that is to say, without any connection with organic 

 life. 



A few words must still be said about comets. These 

 heavenly bodies originate somewhere in the neighbourhood 

 of the orbit of Pluto where the condensation of methane can 

 occur. According to F. L. Whipple*^ the nucleus of comets 

 consists of finely dispersed dust containing all the elements 

 which are commonly met with in the silicate and metallic 

 phases of meteorites. 



There are also present in the nuclei of comets particles of 

 frozen liquids and gases, compounds of carbon, hydrogen, 

 nitrogen and oxygen. 



When it approaches the Sun the substance of a comet 

 begins to emit light and can therefore easily be submitted 

 to spectroscopic investigation. The spectrum of the head of 

 a comet shows that it consists of chemical compounds. In 

 particular, hydrocarbon bands may be seen, indicating the 

 presence of ch., ch and ch+. 



