hausted at the bottom, in reversal of the ordinary process, and under this condition it does not produce the draft or cause the sudden cooling that are so objectionable under the usual method of ventilation.
Work of the United States Fish Commission.—In the work of the United States Commission of Fish and Fisheries, the summer of 1890 was spent by the steamer Albatross in Bering Sea, where the principal banks frequented by the cod were surveyed. The season was too short to complete the work, and it will have to be resumed at some future time. The position of the western margin of the continental platform was, however, defined for a considerable distance, and a good beginning was made toward a knowledge of those physical and biological features of the sea which relate to the habits and distribution of the fur seal and other aquatic mammals. By the surveys of the coasts of Washington, Oregon, and California, the contour of the continental border has been developed from the shore line into depths of two hundred fathoms as far south as Point Conception, while the region between that place and San Diego had been previously explored. Temperature, density, and biological observations in different parts of San Francisco Bay indicate that the waters of that region are not, as has hitherto been supposed, unsuited to the breeding of Atlantic coast oysters. A scientific investigation was made with the Albatross during the early part of 1891, under the direction of Prof. Alexander Agassiz, of the waters lying off the western coast of America between Cape San Francisco and the Galapagos Islands on the south and the Gulf of California on the north. The most extensive and important operations on the Atlantic coast were conducted in the interest of the oyster industry, in the coast waters of South Carolina and Maryland and Virginia, and in Long Island Sound. Dr. Bashford Dean, of Columbia College, was commissioned to study the methods of oyster culture practiced in European countries and to prepare a series of illustrated reports concerning them. The physical inquiries in the mackerel region off the southern New England coast, under the direction of Prof. William Libby, Jr., were continued in 1889 and 1890; and the investigations respecting the interior waters of the country were conducted in twelve States and Territories on an extensive scale and with important practical results. The work of the Division of Fish Culture was continued at twenty-two stations in fifteen States.
The Theory of Special Assessments.—According to the study of this subject made by Victor Rosewater (Columbia College Series), the underlying principle of special assessment for benefit first appeared in this country in the provisions of a provincial law of New York in the year 1691. The effective clause of this statute was copied from an English act passed in 1667, and re-enacted in 1670, to regulate the rebuilding of London after the great fire. Thus the idea was not, as some have supposed, a native American one, but the substance of the plan had been put into English books twenty years before. The New York law remained unrepealed, but inoperative, till 1787, when it was adapted more closely to existing necessities. This method of raising revenue for local improvements remained for a long time peculiar to New York, It did not begin to extend to the other commonwealths till after the people had begun to recover from the effects of the War of 1812. The first development of the system, therefore, corresponds roughly with the movements for the construction of internal improvements covering the years just before and after 1830, and dying out with the crisis of 1837. The era of premature railway building about 1850 witnessed another movement of the kind in the newer States and Territories. The last movement, begun immediately after the close of the civil war, was more general than the others; has not yet wholly ceased; and has passed over into Toronto, Canada. The justification of the policy of special assessments is to be found in the principle that where an expense is to be incurred by a local authority which results in special, distinct, and measurable advantages to the property of particular persons, it is more equitable that those who benefit thereby should contribute to the expense to the extent of those benefits than that the burden should be placed upon others who have received no such special advantages. Among other methods of recovering the expense of improvements, besides
