from the navigators themselves, but from various outside commercial and industrial concerns and individuals whose interests are related in some measure with lake improvement.

Water levels. The stages of water in Lakes Superior, Michigan, Huron, Erie, and Ontario in the following table are from gauge records at the places named, and are referred to mean tide at New York, adjusted levels of 1903.

Monthly means of water level for stations named, expressed in feet above mean tide at New York.

602.86 602.95 603.08 603.26 603.14 602.74 602. 47 602.13 602.04 602.25 602.49 602.67 581.36 581.26 581.19 581.06 580.76 580.44 580.27 580.21 580.33 580.71 580.98 581.36 581.55 581.53 581.36 581.26 580.95 580.50 580.38 580.30 580.29 580.66 580.95 581.40 573.41 573. 10 572.84 572.49 572. 12 571.77 571.52 571.31 571.18 571.83 572.46 572.98 247.78 247.56 247.17 246.84 246.33 245.75 245. 60 245.28 245.06 245, 80 246. 10 246.44

The elevations of "high water of 1838" for each lake, so often referred to, are as follows (levels of 1903):

There is also herewith a sheet showing the monthly mean water levels of all the Great Lakes from January, 1860, to June, 1905, both inclusive. (See Pl. 1.)

Investigation of lake levels.-The principal field work of the year was the collection of lake temperatures for the determination of evaporation from the lake surfaces and the winter discharge measurements of the St. Marys River at Sault Ste. Marie. In office work a large amount of rainfall data was collected and tabulated.

The following table gives a summary of discharges, as so far determined, corresponding to the mean elevations of the various lakes for the last forty-five years:

a Includes 1,200 cubic feet passing out through Erie Canal and 1,100 cubic feet through Welland Canal.

For the continuation of the work of investigating lake levels not less than $10,000 should be provided for next year.

A matter of greater immediate importance to the commercial interests of the Great Lakes is the bringing up to date of the existing Lake Survey charts, their issue in colors, and the extension of the series to completion on a comprehensive plan.

The original charts were prepared with reference to a navigation calling for a draft of only 12 feet. The soundings were referred to planes representing mean or average stages of water, and general depths exceeding 18 feet below such planes were not closely developed; but present conditions of commerce demand that the bottom be now accurately charted to depths of not less than 30 feet in the open lakes and 25 feet in their connecting rivers or straits, and these depths should relate to "low-water" stages instead of to the "mean stages' referred to above. This calls for extensive surveys and a vast amount of office work, all of which must be done with great care and accuracy. The work has been inaugurated with a considerable plant and force, and means should be supplied to carry it to completion as rapidly as possible. An expenditure of $115,000 during the year ending June 30, 1907, will be necessary for such reasonable progress as the circumstances of the case require.

I therefore recommend and, so far as permissible, urge that the appropriation for the year 1907 be made to cover the two amounts above indicated, as follows:

For survey of Northern and Northwestern Lakes, including all necessary expenses for preparing, correcting, extending, printing, and issuing charts and bulletins, and of investigating lake levels with a view to their regulation, to be immediately available and to remain available until expended, one hundred and twenty-five thousand dollars.

Money statement.

July 1, 1904, balance unexpended.

March 9, 1905, amount allotted from sundry civil act approved March 3, 1905..

$198, 698. 24

95,000.00

July 1, 1905, amount covered by uncompleted contracts.....

381.77

Amount that can be profitably expended in fiscal year ending June 30, 1907, in addition to the balance unexpended July 1, 1905

125,000.00

Dates and amounts of appropriations for surveys of Northern and Northwestern Lakes.

Printing and issue of charts for use of navigators and electrotyping copperplates for chart

Surveys, including investigations of lake levels, correcting, printing, and issuing charts and

June 6, 1900.

March 3, 1901

June 28, 1902.

March 3, 1903

bulletins.