manner of taking, [4].
Sampling, [1], [3], [4], [5], [56], [177].
accuracy, [5].
percentage of error in estimates from, [11].
precautions against fraud, [7].
Saving of fixed charges, [155].
Secondary alteration, [24], [25], [26], [30].
enrichment, [21].
Security of investment, [158].
Self-dumping skip, [77].