95 



2249 



2245 CENTRIFUGE, "Celeritas," same as No. 2244, but with Arm for holding 

 four Tubes, with four Aluminum Shields, two gradu- 

 ated and two plain Tubes. This machine is capable of 

 doing the work of two ordinary centrifuges $14.50 



2246 CENTRIFUGE, "Celeritas," same as No. 2244, with two Tubes for the 



examination of Urine and Haematocrit for the exami- 

 nation of Blood and Sputum 15.00 



2247 CENTRIFUGE, "Celeritas," same as No. 2246, with four Tubes for the ex- 

 amination of Urine and with Hsematocrit for the 

 examination of Blood and Sputum 20.00 



2249 CENTRIFUGE, Purdy Electric, with Adjustable Speed Regulator. 



In order to regulate the speed of the Centrifuge more delicately than is possible 

 with the regular device attached to the instrument and to obtain any rate of speed 

 desired within the scope of the motor or to keep the instrument at a fixed speed where 

 the current varies or the load is increased, a speed regulator is necessary. It is often 

 important that an entire series of experiments should be carried on with an absolutely 

 uniform speed. This is mostly not possible without a speed regulator, owing to the 

 varying strength of all electric currents. Again, extremely fragile sediment must often 

 be handled with medium speed, while very light sediments require the highest speed to 

 produce sedimentation. 



The speed regulators can be supplied with any of the Purdy Centrifuges, Nos. 

 2238-2243 inclusive, for either the direct or alternating 60 cycle current of 100 to 115 

 volts at an additional cost of $9.50 



THE PURDY CENTRIFUGE FOR THE 220 VOLT DIRECT CURRENT 



We supply the Purdy Centrifuge for the 220 volt direct current in all cases with 

 the speed regulator. It is supplied in all combinations given under Nos. 2238-2243 

 inclusive, at an additional cost of $14.50 



