( 66S ) 



Let lis now see vvlial the (inaiititative (Ictci-niiiuilioiis ot'tlie iiilmtlon 

 prodiicls of llie iKiloi'eii iKMizeiies luixe t;ui,i2,lil us: 



C,.. H. Fl. 



a. tl, CI. I C, fl. Dr. 1 C, H, J 



nitration 

 torn p. 0°. 



niti'atidn 

 t(Mnp. -30^ 



From Ihis iiiti'atiou of hciizeiie fluoride it is also shown iu the plainest 

 manner that the intluence of the lluorine atom oJi the [losition of 

 the nitro group is quite diiferent from that of other halogens 

 which in this respeet behave very similarly. 



Groningen, Dec. 1903. 



Lah. Univers. 



Chemistry. — ''Description of an appavidns for Tegidating the 

 pre^ssure when (listiliijtg under reduced pre.^i<ure.''' By Jan 

 RuTTEN. (Communicated by Prof. S. HooGEWKKFt). 



(Communicated in the meeting of 1^'ebiuary 27, 1904), 



When distilling under reduced [)ressure it is always of importance 

 to kee[) this constant during the distillation : moreover, the pressure 

 during the operation must frequentl}' be a delinite one. This is, for 

 instance, the case in the testing of niiiieral oils, where it is generallv 

 required that a definite quantity shall distill over at a delinite [)ressure, 

 which is in general considerably less than thai of the atmosphere, 

 and at a deiinite temperature. 



As it is not possible to keep the pressure sufticiently constant by 

 the admission of air, the quantity of which is regulated by a screw- 



