adapted for use as a reliable fixed point in thermometry; a research aiming to free naphthalene from obscured impurities.

The problem of producing pure oxygen in large quantities has now been solved by newly devised apparatus. The oxygen is used for combustion purposes in precision testing of heat values. A number of highly purified gases for heat determination have also been prepared as a basis for gas engineering tables. Such tables will permit the calculation of the heat value of illuminating gas direct from the chemical analysis.

During the year there were published the results of 44 investigations concerning standards, measuring instruments, and methods of

measurement.

DETERMINATION OF PHYSICAL CONSTANTS.

Physical constants are the measured data relating to materials and energy which underlie scientific and technical work. Hence they are of fundamental importance in the work of standardization. Among these would be the melting and boiling points of materials, flash points, breaking and crushing strength, hardness, density, expansivity, and conductivity. A few researches of this character may be cited, e. g., the thermal expansion of 25 different specimens was determined for ranges from below freezing to above the boiling point of water; the density and thermal expansion of linseed oil and turpentine was determined, a constant much used in specifications for purity.

In connection with standards for commercial use, the density of ethyl alcohol is of great importance. This physical constant has been under investigation at the Bureau for several years. The alcohol was purified by the most refined methods which could be devised and the density was determined with high accuracy, probably correct to within 1 part in 100,000. The values of the densities of alcohol-and-water mixtures were determined with an accuracy within 2 parts in 100,000.

A physical constant of importance in atomic-weight work is the atomic weight of bromine, which is now being determined by the Bureau as a logical conclusion to similar work on chlorine. materials have been purified and the work is well advanced.

The

A number of boiling-point and freezing-point determinations have been made for use in temperature work. For example, the boiling point of sulphur has been accurately determined for use as a fixed point in thermometry corresponding to the temperature 444:7 C. The concordance of this work gives promise of international agreement on the scale of temperature above the boiling point of water, ranges in which uncertainty has always existed.

In practically every line of work similar researches are in progress, with the aim of providing reliable data upon which to base units and standards. The pressing need for such work and its utility can hardly be overestimated.

DETERMINATION OF THE PROPERTIES OF MATERIALS.

The determination of the quality of materials is a most important problem in the industries, since to the consumer quality is the real object of purchase and sale. The modern view that value rests upon measurable properties which combine to fix the quality is the basis for the determination of quality by measurement.

The materials tested by the Bureau during the year include such materials as the cements, metals, and other materials used in the construction of the Panama Canal; the supplies for the executive departments at Washington; and bookmaking materials—paper, type, ink, cloth, and glue-used by the Public Printer for Government documents. Here, as elsewhere, the investigations have resulted in great saving and efficiency in buying by basing such purchases upon tested quality and price alone.

Of the determinations of the properties of materials involving chemical work there were during the year 8,868 separate tests for practically every department of the Government and many times this number of separate determinations. Important investigations are in progress in connection with the properties of paper, paper pulps, and the composition and manufacture of paper. The properties of the new monel metal are being investigated to determine its suitability for laboratory utensils and appliances. The properties of materials such as steels, irons, refractory materials, and other materials of construction-have been under investigation to determine their suitability for the particular uses for which they are intended. The purity of platinum sold for chemical purposes has been studied with the greatest care to ascertain the nature of the impurities present a research of vital importance to chemical analysts. In this work the Bureau has cooperated with other laboratories concerned. The Bureau is cooperating, also, in an international comparison of the magnetic properties of materials.

TRADE WEIGHTS AND MEASURES INVESTIGATION.

The investigation of trade weights and measures conditions throughout the country, for which Congress has made special provision, has practically been completed and will form the subject of a special report. Every State in the Union, with the exception of Arkansas and Oklahoma, has been visited, and inspections in the two mentioned will be made in the near future.

Of the incorrect apparatus found, a large proportion discriminated against the consumer, and consequently furnished the strongest argument for the establishment of inspection services by the States. The investigation has attracted the widest attention and has resulted in either the enactment by the States of laws to render efficient the old weights and measures laws or the enactment of entirely new ones.

Altogether, the legislatures of 26 States in different parts of the Union have acted upon the information obtained by the Bureau, and others are preparing to take up the matter at the next meeting of their legislatures.

BUREAU OF FISHERIES.

FISH CULTURE.

The fish-cultural efforts of the Bureau were directed chiefly toward the development of present resources and the increase of the output by extension of operations over a wider territory in fields contiguous to existing stations. One new permanent station was added to the existing 36 of this class, the establishment at Homer, Minn., being completed and opened at the beginning of the year. The cultivation of the buffalo fish, one of the most important food fishes of the Mississippi Valley, and not hitherto propagated artificially, was successfully undertaken, and investigations were instituted at the Homer Station with a view to propagating the shovel-nose sturgeon, the spoonbill, the catfishes, and other heretofore uncultivated species of that region.

The possibilities of fish-cultural work are practically unlimited, being gauged only by the funds and experienced men available for opening up new fields. This is particularly true with reference to the Pacific coast salmons, the trouts of the Rocky Mountains, the commercial fishes of the Great Lakes, and most of the anadromous and marine species of the Atlantic coast.

The year's output of fish and fish eggs totaled more than three and one-half billion. Of these, 558,000,000 were eggs, over 3,000,000,000 were fry, and nearly 15,000,000 were fish of fingerling, yearling, or adult size. The output was nearly 13 per cent greater than in 1910, this showing being largely accounted for by the adoption of new methods and the utilization of improved appliances, resulting in increased efficiency and diminished expense. The species whose larger numbers constitute the total increase for this year are the chinook salmon, Atlantic salmon, steelhead trout, brook trout, rainbow trout, grayling, pike perch, yellow perch, white perch, small-mouth black bass, buffalo fish, pollock, haddock, and lobster. The output of Atlantic salmon was double that of any previous year.

The stocking of depleted public waters and private ponds, lakes, and streams is a feature of the Bureau's work which grows yearly in interest to the public, the number of applications for fish for such purposes numbering 10,393 this year. Over half of these applications were for black basses, crappies, sunfishes, and catfishes for stocking artificial ponds on farms, there being widespread realization that private fish ponds can be made a valuable adjunct to farming-as a food supply for home consumption and as a source of income.

BIOLOGICAL INVESTIGATIONS.

The oyster was again the subject of major activities. The survey of the natural oyster beds of Delaware, in progress at the beginning of the fiscal year, was concluded and its results reported, to show the dangers threatening an important industry and to serve as a basis for reforms which it is hoped will be instituted by the State. Immediately upon the conclusion of this work in Delaware similar surveys were undertaken in Alabama and Mississippi, at the request of those States, and reports thereon are in course of preparation.

During the latter part of the year special study was given to several destructive enemies of the oyster, in the effort to develop measures which will guard planted oyster beds against such inroads.

The systematic investigation of streams in the Mississippi Valley with reference to their pearl-mussel resources was continued, and the trained personnel of the station at Fairport, Iowa, is engaged in the collection of data to aid in the formulation of fishing laws which will adequately protect the mussels. This station has also been engaged in propagating and distributing mussels in the waters in its vicinity.

Investigations of a tumorous disease in cultivated fishes which extensively affects Salmonidæ, especially trout raised under domestication, have been conducted almost continuously throughout the year. Though results are inconclusive as yet, it seems probable that this work will result in a very considerable saving to the Bureau by making possible a reduction of the present mortality among artificially hatched trouts and salmons. In respect to the possible relationship of the disease to analagous affections of human beings, the investigations have progressed satisfactorily, but permit of no conclusive statement at this time.

The effects of industrial wastes upon fishes, a subject important from the viewpoint of many industries other than the fisheries, has received considerable attention in the investigation of several fish epidemics and numerous experiments with various kinds of pollutions. Investigations of lakes and rivers in several States have been continued with profitable results, notably in the work done in cooperation with the Wisconsin Geological and Natural History Survey. These investigations include lakes in Wisconsin, Minnesota, New York, Maine, New Hampshire, and Idaho, and a somewhat similar procedure has been undertaken in examination of the Illinois River with respect to its pollution and biological changes which have resulted from the diversion of the flow of Chicago River.

The biological laboratories at Woods Hole, Mass., and Beaufort, N. C., have been open as usual, and profitable researches have been conducted both by the special investigators in the service of the Bureau and the independent workers from various institutions of learning.