CHEMICAL SELECTION OF MOTHERS. 99 



are being examined at a time, it is better to have at 

 least seven for each series of lOO beets. For each 

 series of the laboratory in turn, the small cyHnders 

 obtained are placed in regular order, one alongside of 

 the other, and cut at equal length by a parallel blade- 

 slicer of special construction, capable of cutting 1200 

 per hour. 



The samples are then replaced in their respective 

 numbered compartments of the frame. It is an aston- 

 ishing fact that these small cylinders have nearly the 

 same weight, and the error committed is so slight that 

 its influence upon the whole series of experiments need 

 not be considered. The exact weight for the demands 

 of these analyses should be 6.512 grams or 26.048-^-4 

 grams.* With the view of determining what their 

 exact weight is, lOO were weighed in five series 

 of 20; the average for each series was 6.506 grams, 

 6.512 grams, 6.503 grams, 6.527 grams, 6.518 

 grams, or a variation of o.oi to 0.02 grams; an approx- 

 imation quite sufficient for all practical purposes. 



It is interesting to note that several preliminary 

 weighings are necessary; the slicing blade is adjusted 

 accordingly, and, when once arranged, can be relied 

 upon. The Hanriot machine (Fig. 38) in which these 

 small cylinders are placed and reduced to a fine pulp, 

 consists of a conical box, H. made of hard bronze, with 

 lateral tube, the appliance itself being mounted on a 

 tripod, which may be screwed upon a table, s. z' and z." 

 Inside the bronze box are a series of grooves, made in 

 the direction of the generatrix of the cone. Against 

 this surface revolves, at a velocity of 2200 to 2500 

 revolutions per minute, a solid cone, which has a series 

 of teeth all at an angle of 45 degrees to the axis of rev- 

 olution, thus facilitating the exit of the pulverized beet, 

 and also of the water during washing. The cylinder 



•This weight varies witTi the polariscope used. For the French 

 apparatus it would 16.29-H=4.07 grams. 



