But the greatest objection of all is to the schedules created by the law of 1850. The number of inquiries is limited by that law to one hundred, though why that number should be selected as the limit, except at haphazard, is a mystery. It is purely arbitrary, and in its practical working is mischievous. Statistical inquiries ought to be exhaustive, whether the questions asked are ten or ten thousand. To limit the number to one hundred requires the lumping together of incongruous facts or the entire omission of some of prime importance. Of what real value is the answer to the question, "Kind of motive-power?" in relation to manufactures unless other details are given? Yet only such questions can be asked where the margin is so narrow. In the census of Massachusetts for 1875, 304 inquiries were made, embracing 1337 topics; and so satisfactorily was the work done that out of a population of 1,651,912 only 43 persons were unaccounted for when the statistics of occupations were compiled; while in the United States census of 1870 the number thus unaccounted for exceeded 1,000,000. In Rhode Island no less than 561 inquiries were made in the census of 1875, and the result is the most complete census--not merely of persons, but of every kind of manufacture and production--yet taken in any State. The returns of cotton, woollen and iron manufactures show what can and ought to be done in that direction for the whole nation in 1880. They answer the requirements set forth by the superintendent of the census of 1870 by presenting "tables so full of technical information as to become the handbook of manufacturers."