Date. TABLE B.-Sub-surface velocities in nearly the same depth of water, St. Lawrence River, 1868—Continued. 70 70 75 80 OFFICE LAKE SURVEY, July 1, 1869. SIR: I have the honor to submit the following report on the meteorology of the lakes for the past year. Tables A show the maxima, minima, and mean of the barometer and thermometer, and the amount of rainfall for the months, seasons, and years, for each year since the commencement of the observations. In the following table I, is given the mean and range of the temperature at each of the stations which are arranged according to their respective latitudes. In Table II the stations are arranged according to their heights above the sea, and the mean and range of the barometer given for each place. Tables C are condensed from tables B and show the maxima, minima, and mean of the observations for the whole time observed. Tables III have been compiled from the reports of the Smithsonian Institution and of Toronto and other meteorological stations; and they show the mean monthly and yearly temperature for a series of years at a number of places in the neighborhood of the great lakes. They are graphically represented in the accompanying sketches on each of which the isothermal curves for two months, half a year apart, are given. TABLE C.-Maximum, minimum, and mean of the barometrical pressure reduced to 32° Fahrenheit +28 inches. 1866. 1867. 1868. TABLE C.-Yearly means and range of barometrical pressure reduced to 32° Fahrenheit + 28 inches. 1861. 1862. 1863. 1864. 1865. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. Mean. Range. 1859. 1860. TABLE C.-Maximum, minimum, and mean barometrical pressure, reduced to 32° Fahrenheit, for seasons and years, +28 inches. |