The boilers are fixed at a considerable height over the large ovens within which the fire is made. Each boiling-house has two ovens, one for heating the caldron and the other for the three or four coppers. The mouths of these are about half as broad as the ovens themselves. Enormous rolls of timber and the branches of trees are prepared for the purpose of supplying these ovens with fuel. The negroes sometimes find it almost impossible to approach them, owing to the excessive heat which they throw out[161]. The manner of conducting the manufacture of sugar was, from what I can collect, very similar on the whole, in the Columbian islands about the beginning of the last century, to that which is practised at present in the parts of Brazil which I visited. The _temper_ which is usually made use of is the ashes of wood calcinated, of which there are certain species preferred for this purpose[162]. Lime is commonly used in the Columbian islands, and few planters of Pernambuco have lately introduced this alkali into their boiling houses, but there exists a general prejudice against lime, under the idea that the sugar with which it has been made is unwholesome; and this has prevented many persons from adopting it. No difficulty would be found in introducing it, among the planters themselves, because the ease with which it is obtained, would soon urge them to give it a fair trial. Some plantations sell a great portion of their sugar and rum upon the spot, and several of the lesser ones grind all their canes for the purpose of making melasses, which they distil themselves, or sell to the distillers of small capital, who are very numerous; therefore to the owners of these plantations in particular, the opinion of the people of the country is of considerable moment. The planters of Brazil invariably follow the system of claying their sugars, but the process is too generally known to require any account of it in this place. THE STILL-HOUSE.