────┬──────────┬──────────────────────────────────────────── │ │ LEAD-POISONING—SHAFT FURNACES │ ├─────────────────────┬────────────────────── YEAR│NO. OF MEN│ CASES │ DAYS OF ILLNESS │ ├─────┬───────────────┼─────┬──────────────── │ │TOTAL│PER 100 PERSONS│TOTAL│PER 100 PERSONS ────┼──────────┼─────┼───────────────┼─────┼──────────────── 1902│ 250 │ 58 │ 23.2 │ 956 │ 382.4 1903│ 267 │ 59 │ 22.1 │1044 │ 391.0 1904│ 232 │ 24 │ 10.3 │ 530 │ 228.4 ────┴──────────┴─────┴───────────────┴─────┴──────────────── If it were possible to make the necessary distinctions in the case of the large shaft furnace, the diminution in sickness from lead-poisoning would be still more apparent; for, among the furnace attendants proper, there has been no illness; all cases of poisoning have occurred among the men who prepare the charge, who break up the roasted material, and others who are occupied with subsidiary work. Some of these are exposed to illness through their own fault, owing to want of cleanliness, or to neglect of every precautionary measure against lead-poisoning. Thus far we have dealt only with the advantages and improvements of the Huntington-Heberlein process; we will now, in conclusion, consider also its disadvantages. The chief drawback of the new process lies in the difficulty of breaking up the blocks of the roasted product from the converters, a labor which, apart from the great expense involved, is also unhealthy for the workmen engaged thereon. Seemingly this evil is still further increased by working with larger charges in the 10 ton converters, as projected; but in this case it is proposed to place the converters in an elevated position, and to cause the blocks to be shattered by their fall from a certain hight, so that further breaking up will require but little work. Trials made in this direction have already yielded satisfactory results, and seem to promise that the disadvantage will in time become less important. Another unpleasant feature is the presence (in the waste gases from the converters) of a higher percentage of sulphur dioxide, the suppression of which, if it is feasible at all, might be fraught with trouble and expense.