120 



The substances lliat are \'\(\u'n\ al uidiiiary lempeiatmes were 

 exposed in a iDore simple glass a|)paralus ivilli a (liiii walled lower 

 pai-l, which üüed on the same camera, while again the camera 

 was evacuated. 



§ 3. HesidU. We have exposed li(piid oxygen, liipiid argon, benzene, 

 water, aethjlalcohol, aethylaether, formic acid, caibonic disulphide, 

 bromiuiïi. 



Of these carbonic disnl|)hide and bromiuu) (in glass tube) gave 

 no distinct diffraction tigure ^). 



The other liquids gave first an intense almost circular diffraction 

 ring. Fig. 2 shows the diffraction ring of oxygen. 



Argon was exposed twice, once in an aluminium tube and once 

 in a glass tube. Of these only') the first one gave a distinct diffrac- 

 tion figure. 



In table I fp represents the half top-angle of the cone formed by 

 the diffracted Ron t gen rays. 



TABLE I. 



By the agreement between the diflfraction rings of oxygen and 

 argon we might come to the liypothesis that these rings are due 

 to the same impurity f.i. to small ice crystals. This was however 

 proved to be not the case. Therefore oxygen namely was first dried 

 by KOH and P^Oj, then liquefied and destilled in apparatus dried 

 beforehand and finally poured through a filter of cotton wool into 



') The probable reason for this is, that the Röntgen rays are absorbed to such 

 a high degree by these substances, that the Röntgenlight diffracted by the liquid 

 on account of its small intensity cannot be distinguished from that diffracted by 

 the glass. 



3) Probably by the reason mentioned in note 1. 



