274 



humboldt's cuba. 



the idea of those inventions, which have since been 

 extended with some usefulness. Wooden covers 

 placed on the clarifiers hastened the evaporation, 

 and induced me to believe that a system of covers, 

 and movable ladles suspended with counter- weights, 

 might be usefully extended to the other kettles. 

 This idea is worthy of examination, but we must 

 graduate with care the quantity of syrup, the crys- 

 tallizable sugar obtained, and that which is lost, the 

 fuel, time, and pecuniary expense of the experiments. 



An error has generally prevailed in Europe, which 

 has had no small influence in the study of the effects 

 a cessation of the African slave trade might produce, 

 in supposing that in the so-called sugar colonies of 

 the Antilles the greater part of the slaves are 

 employed on the sugar estates. There is no doubt 

 that the cultivation of the sugar cane is one of the 

 most powerful stimulants of the slave-trade, but a 

 very plain calculation proves, that the mass of slaves 

 in the Antilles is three times greater than the num- 

 ber employed on the sugar plantations. Ten years 

 since I stated, that if the 200,000 boxes of sugar, 

 which Cuba exported in 1812, were made on the 

 larger plantations, 30,000 slaves would suffice for 

 that branch of industry. 



It is estimated in Cuba that for the production of 

 1,000 boxes of clayed sugar, 150 negroes, on an 



