372 PROCEEDINGS OF THE SCIENTIFIC ASSOCIATOIN. 



the liquid to be evaporated come in contact with, many hun- 

 dred feet of evaporating surface. A blast of air along this 

 surface as proposed by the inventor, but not put in execution 

 by him, would, if heated or even dry, have more than doubled 

 the evaporative effect. Dmitri Davidou then proceeds to 

 state the results obtained in the following language : " Les 

 produits bruts que j'ai obtenus l'annee passee (1836) de la 

 betterave tres alteree, a l'aide de mon plan incline (apres 

 lequel j'achevai la concentration du sirop dans un cylindre 

 tournant) avaient la blancheur de la neige et offraient l'aspect 

 du sucre en pains par le rapprochement compacte de leurs 

 crystaux, mais comme les sirops n'avaient point subi Faction 

 violente du feu, la saveur, etc." 



These results are brilliant, and it is not astonishing that a 

 pure juice (for Davidou insists on purity as essential) should 

 when rapidly evaporated by steam in a copper vessel at a low 

 temperature produce a white concrete, the wonder is that a 

 system so simple and presenting such advantages, should 

 have remained in abeyance till within the last 3 or 4 years, 

 when it has been revived by Mr. Fryer in the introduction of 

 the Concretor. This last, a modification of the inclined plane 

 and cylinder of Davidou, appears to be a wonderful improve- 

 ment on the canon coppers, producing in a single concrete 

 form, easily made, handled and shipped with little or no loss, 

 what was formerly shipped with great trouble as the two 

 separate articles, sugar and molasses with an eventual loss 

 on their aggregate of seldom less than 12 or 14 percent. 

 Mr. Fryer rates the gain at something over 4 per ton by 

 employing the Concretor ; I am inclined to place it much 

 higher if the apparatus be worked with care, not that it will 

 ever give or was ever intended to give a white concrete like 



