398 



Motion of Gaseous Bodies. 



52980. 1 : 15. 



52991. 1:13. 



52 992. 1 : 6. 



52,990. Mercury Vacuum Pump after Spies, Figure (Ztschr. f. d. phys. u. chem. I". 8. s <' 

 1894/95, p. 336) . 7. 0. () 



r>L'. '.!!. Automatic, Constant-action Mercury Vacuum Pump after Kahlbaum, Figure, for 

 physical and chemical purposes; consisting of a Sprengel Mercury Air Pump combined 

 with a Mercury Hoisting Apparatus (Wied. Ann. 53, p. 199, 1894; Ztschr. f. Instru- 

 mentenkunde, 13, p. 73, 1893) 14.1(1.0 



r>L', <Mi*. Rotary Mercury High-Vacuum Pump with iron Drum, Kohl's System, German Patent 

 applied for, Figure, with toothed gearing and driving wheel. The Pinup can be driven 

 either by hand or motor l. r >. (). 



With the aid of this Pump, in conjunction with a. preliminary pump (the hitter must produce 

 a vacuum of 15 10 mm) it is possible to obtain the highest vacua that can possibly be obtained 

 with Mercury Vacuum Pumps, and this in the minimum of time. This Pump is therefore cminenth 

 suitable both for the manufacture of glow lamps. Ilontjien tubes, etc. and For demonstrating in physical 



instruction, also for use in laboratories. As regards a Preliminary Pump it is advisable to use one of 



the Rotary oil Vacuum Pumps Nos. 62,901 62,906, or aWaterAir Pump, A charge of about 1,6 litres 



i-O k^) mercury i> neces-ary and should if required be ordered separately. 



The Pump is of small and compact construction, is rapid in its action, and contains no vl :i -s. 

 porcelain, or rubber parts. Tue rotating part and the carcase are of iron, bciui; thus unbreakable. 

 The Pump is very smooth in its action. 



Kvery Pump is tested in our works for its efficiency by means of a Mac l.eod Vacuum Cau.nc 

 and a certicate i;i\ iui: re.-nll of teM i> >npplied with the Pump. 



r.L'.IMt:!. - - The same Rotary .Mercury High-Vacuum Pump with ' ',"' H. P. 110 volt 

 Direct Current Motor, Figure, with starter, switch, connecting lead i m long, with 

 plug box and plug, with Leather cord; the whole mounted on one board --. '. o 





