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 214 THE CONDOR Vol. XV thought process and o 'record' the terms by which I seek to make a color name clear to my own apprehension. Accepting Ridgway's arrangement and spacing ' of colors as a practical fixity, and referring all colors to the thirty-six-hue base, I designate the three diminishing tints of each local base as tint, half-tint, and quarter-ti nt, respectively; and the shades as shade, double-shade and triple- shade, respectively. This is not accurate in either case if we base our compari- son upon percentages of black or white, but it is practically correct if we appeal to the eye and that is what we are after. In like manner referring back to the normative hues all successive changes affected by additions of neutral gray, I speak of gray (32%), double-gray (58%), triple-gray (77%), quadruple-gray (9o%), and quintuple-gray (95.5%)--the last two, of course, rarely required. In this way, the blue of a Valley QuaiFs breast designated in the text of Ridgway as Light Payhe's Gray, is thought. of as the double-gray half-tint of Spectrum Blue; and the buffy of its lower breast, known as Light Buff, is related in thought to the Cadmium Yellow base by saying that it is the gray quarter-tint of that hue. It is thus clearly differentiated from "Cartridge Buff" or "Tilleul Buff", which are as truly light-buffies, but which differ very materially in quality from the arbitrarily named Light Buff. In analyzig a color, that is, in seeking to arrive at its proper designation, the reverse of this process is 'of the utmost importance. One first decides upon its basal or distinctive element, then estimates the relative admixture of gray, then turns expectantly to the appropriate column to determine the tint or shade. As a novice I should never by any 'possibility have guessed that a Valley Quail's breast is light Paynle's Gral-..(indeed, I suspect I shall die iu ignorance of the difference connoted by the nmnes Payne's Gray and Puritan Gray), but I did guess first off,. within one P0int that it was a double-gray quarter-tint .of Spec- trum Blue. A brief experience leads me to the belief that this logical process will always b6 followed, in practical disregard of arbitrary names. For this provision of a logical method of color inference, we are immeasurably indebted to our foremost living brnithologist, Robert Ridgway. PRELIMINARY REPORT UPON THE DISEASE OCCURRING .AMONG THE DUCKS OF THE SOUTHERN SAN JOAQUIN VALLEY. DURING THE FALL OF 93 By FRANK C. CLARKE Special Assistant, California Fish and Game Commission WITIt ELEVEN PI:IOTOGRAPHS AND ONE DIAGRAM BY TI:IE AuTItOR . BOUT the month of August, 9o9, a fatal epidemic broke out among tle water birds, especially among the ducks, of the vicinity of Soleta Lake, 'which lake, now dry, was situated about thirty-five miles southeast of Tulare Lake. ' This epidemic, gradually spreading, raged throughout the hot part of the season till the cool weather of the fall, when it ceased. At this time Soleta Lake was quite stagnant, becoming more so until it finally dried up some two or three year5 later. There were reports of a fatal disease among the water birds the year before, but little attention was paid to them.