The amount of earth-scrap collected on any estate will depend, all other things being equal, upon the labour expended in its collection. Certainly on well-organised estates, having ample labour, the amounts collected are huge in comparison with other estates. The ground at the base of the tree below the latex-spout is systematically turned over with pointed sticks and large clots of rubber are often picked up. Here, again, it is advised that the collected earth-scrap should not be allowed to remain in heaps upon the floor of the factory. It should be placed in suitable tanks containing water, and quite a considerable portion of the cleansing work is thus taken from the machines. CHAPTER VI _TRANSPORT OF LATEX AND COAGULUM_ PERCENTAGE OF FIRST LATEX AND OTHER GRADES.--One of the problems confronting any manager is the question of the percentage of first-grade rubber calculated upon the whole output. Inquiries are constantly being received for advice as to what the various percentages of each grade of rubber should be. This is a question to which no definite list of figures can apply. There are so many little factors influencing the result. Some estates are not particularly careful in collecting tree-scrap. Hence quite a quantity of tree-scrap finds its way into the crepe made from bark-shavings. On the other hand, bark-shavings are not collected systematically on some estates, and the total output is thereby diminished. In consequence the first-grade rubber shows a higher percentage than it would otherwise. Again, if the earth-rubber is not regularly collected the percentages of the best grades are higher than they should be. In comparing the percentages of each grade of rubber from any two estates, therefore, one should have all the information possible as to the various working details of the estates. Without wishing to lay down any definite proportions which can be applied to all estates it might be said that, taking averages over a large number of estates, the percentages to be aimed at are: First-grade latex 75 per cent. to 80 per cent. Other grades 20 " " 25 " For these figures one promises that all lower grades are collected and accounted for carefully and regularly. The distribution of the lower grades will depend upon the field practices of the particular estate, but the following list might be given for an estate keeping all lower grades distinctly separate: First-grade latex 75 per cent. Cup-washings } Coagulated lump, etc. } 10 " Tree-scrap 9 " Bark-shavings 4 " Earth rubber 2 " --- 100 "