Sir: In lieu of a simple list of the plants obtained in Colorado during tlxe explorations of last summer, I have the honor to present you herewith a condensed Synopsis of the Flora of the Territory, prex)ared in con-'A, Zafliyrufi/^( ninth line from bottom^) jiut^'A Lafhj/rus." *ElBES FLORIDUM, L'ller./' put "RlBES FLORIDUM, L."' (E.NuttalUi, T. & G.," (sixth line from top,) put '' (E, KuttalliijToTT:' ' O. hrcvistijla,^^(eighth line from top,) put '• O. hrevlHbjllsP 'SOUDAGO L.VXCEOLATA5 T, & G./' put "SOLIDAGO LAXCEOLATA, L." 'HELiorsis LAEYis, Pursh," put "HELiorsis LAEVis, Pers." 'MiMULus FLORinrxnus, Gr./'pnt *'Mimclus floribuxditS, Dough" 'DC. Prod. 10, p. 1, 331," (sixth lino from bottom^) put "DC. Prod. 10, p. 331." ' ACERTES DECUMBEXS," put^* ACEKATES BECCMBENS." . Dumont," after Suxda m^vhitima^put^*Dumort." SUEniERDLV C.VNADEXSIS, L.," put "SllEPUERDIA CaXADEXSIS, Nutt." ' IIUMULUS LUPULUS," put "H. LUPULUS.'T ixus aristata, Eugelm, DC. Prod., L c, p. 400," put "Pxxus Balfouriax-a, Murr., (P. aristataj Engclm.") *MoxTAXUS," (third line from the top,) put "MOXTaxcs." ' var. MixoR, Olney," put^'var MIXOR, Boott," Orthotrichum IlATxir, Sully. & Les^ix.," put^' O. HAI.LII Lesqx.'Ŝ 'ar. S. alpinum/^(ninth line from top,) put "var. J. alinnum." 'EXGYRnvM," (first line at top,) put "eugyrium." CTEIDIUM," (thirteenth line from bottom,) put " CTEIxidium." 'EXDOCOCEUS/' put " EXDOCOCCUS." 'AgaRICUS LACCATUS, Scap.," put A. LACCATCS, Scop.'' 'LeXZITES SEPIRIA," put "L. SEPIARIA." *PUCCIXIA PORTERl/' put "P. POKTERI.'P ec.," after Peziza ao-ecaxalts^p ut "Peck.'' SYNOPSIS OF THE FLORA OF COLORADO. * Clemati?^DoU(;l.ASII, Hook. Stem Ksiinple, erect, 10-2^I ngli, l-flowered, sparingly liaiiyj^voolly at the jointsj leaves liaiiy, 2-3 pinnatilid; sepals tliick, deep pnr[)le within, paler externally, spreading at 4 SYNOPSIS OF THE FLOEA OF COLORADO. J^c eediii j; 1' in diameter ; petals flal^eHiform, twice exceeding the sub-villous ovalvsepalsj basilar scale small, adnate ; achenia crowded in an oval head, sraootli. tnrgid ; beak rather long, ensiform, scarions-winged on each side.-In the high alpine region, close to the snow. Ball & Harbour, 17 ; Furry. Chicago Lakes at 12,000 feet altitude, June, Coulter. Gray's Peak, 13,000 feet, Bedjield, Eanukculus REPENS, L. ; petals 12-18, spatulate, retuse J stamens very numerous; anthers truncate, appendiculate at the apex, equaling or shorter than the at-length recurved filaments; stigmatic rays of the striate, urceolate ovary 13-21, almost reaching the crenate margin of the umbilicate disk, neither constricted nor beaked toward the apex.-Leaves longer in proportion to their breadth than those of y. adveua;^inus narrower and more closed; flowers very large ; outer sepals greenish and yellowish, inner ones more or less tinged with r red. -^I VIountain -lakes around Long's Peak, Parry, Cold Lake in the SieiTa Madre Eange, at 10,000 feet altitude, Coulter.

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[May 14Pthe black sector affects the flicker curves (such as those given in fig. 3 of the present paper), and perhaps the simplest way to make this plain, is to take a numerical example: suppose then that the amount of white light reflected from 360° of black is equal to that reflected from 24° of the white cardboard from which the disc is made • then if the angular breadth of the white sector is, say, 60°, the total amount of white light reflected from the remaining 300° of black will be equal to the light reflected from 22° of white, and this light is dis tributed evenly throughout the black. Now if this disc is made to rotate until it becomes flickerless, its luminosity or albedo will be rightly expressed as that of a mixture of 60° + 22° = 82° of white, and 278° of absolute black, and if a second disc were made with a white sector of 82°, and an absolutely black sector of 278 , this second disc, when flickerless, would appear of the same brightness as the other disc of 60° white, and 300° imperfect black, but-and this is the point of the illustration-the flicker does not just vanish at the same speed of rotation for the two discs,-for flicker depends essentially upon contrast, and'the contrast between the white and absolute black is greater than between the same white and imperfect black. Let the whiteness or albedo of the white cardboard be expressed numerically by 100, then the flicker in the case of the first disc is produced by the contrast between the 60° sector of white of albedo 100, and the 300° sector of what is really dark grey, albedo 7'3. Thus 7'3 of the white sector's brightness will contribute nothing to the flicker, for the disc may be regarded as being of the albedo 7'3 all over, there being added, where the white sector is, an additional albedo, not of 100, but of 100 -7-3 = 92*7. In order, therefore, that flicker may vanish on a disc of 60° white, and 300° of absolute black, at the same rate of rotation as for a disc of 60° white and 300° of the imperfect black already mentioned, we must lessen the contrast between the white and black of the first disc by reducing the albedo of its white sector in the ratio of 92-7 : 100, and this can be done experimentally by altering the distance of the rotating sector from the source of light. Now the effect of altering the distance of the disc from the source of illumination is shown by the curves of fig. 4, and since the greater the distance from the source of illumination the further the curve lies to the left in this figure, we see that the effect of the imperfection of blackness in the black sector of the rotating disc is to shift its curve further to the left than it would lie if the black were perfect, and thus, as is evident from the figure, to make it of a rather flatter form than it would otherwise b e : it is also evident that unless the amount of light reflected by the black sector is large, the shift in the curve is small, and the difference in form very slight.(2.) The rate of rotation at which flicker appears just to vanish, depends, among...

-On December 10, 1885, the death of J. Roberts Lowrie Esq., in the 63d year of his age, occurred at his residence in Huntilngdon county, Pa. A son of the Hon. Walter Lowrie, at one time U. S. Senator from the state, he was born in the town of Butler. From Jefferson College he received his first academic degree, with honor, in 1842, and devoted himself to the study of law with his uncle, Judge Lowrie, of Pittsburg, afterward Chief Justice of the Supreme Court. As a field for the practice of his profession be chose Hollidavsburg, in Blair county, but a year or two later removed to Warriorsmark, a village at the base of the Bald Eagle Ridge, near the Alleghanies, where he spent the remainder of his life. Having married Mary, the daughter of Mr. John Lyon, the senior member of a firm which owned one of the largest estates in Central Pennsylvania, incluiding farms, furnaces, forges, ore-banks, and many thousand acres of mountain lands covered with forests, he became its legal adviser and the general manager of the domain.Thus situated he had ample meaus and opportunity for the stuidy of the natural sciences, to which he was strongly inclined. Of these, botany was his favorite, as a visitor would soon discover from the full and choice array of botanical works on the shelves of his library and the herbarium which occupied a place in the same room. His love of trees and shrubs amouinted to a passion, and he was well acquainted not only with all the wild arborescent vegetation in his neighborhood, but, soon after coming to Warriorsmark, converted the extensive groUnds attached to his mansion into an arboretum, where now may be seen, after the lapse of more than thirty years, splendid specimens of many beautiful and remarkable species, native and exotic. In the creation of this park he was guided by thorough scientific knowledge and excellent taste. May it long flourish as a monument to his memory.But his attention was not confined to the cultivation of trees and shrubs. To him the entire flora for many miles around his home was an object of special interest. He made large collections of the rarer plants, and by his efforts one species new to science was brought to light (Prunus Alleghaniensis Porter), and a number new to the state, of which may be named hl.ex mollis Gray, Lathyrus ochroleucus Hook., Symphoricarpos racemosus Mx., var. pauciflorus Robbins, Phlox ovata L., Pinus pungens Mx. (since found elsewhere), Listera convallarioides Hook. The circumstances under which the last was obtained will furnish a good illustration of his energy and zeal as an explorer. On a botanical trip to the Bear Meadows, an elevated mountain-bog in Center county, he made his way very slowly, and with great toil for a considerable distance, through a dense wall of rhododendrons to an open space where he gathered the plant, its only known station south of N. New York, and then, with his treasure in hand, by the aid of a compass, struggled back through the jungle to the point where he had entered-a difficult and dangerous feat which occupied...

Since the last papers* the research has been continued at intervals through the nine years. Some numerical errors on pp. 325 and 327 in the last paper have been detected by the author, but nothing whicjji in the least degree alters the main results of that paper, viz., that the number of revolutions per second which a disc having a white sector tv, and a black sector 360° -w, must make in order that the flicker may just vanish, under an illumination I, is given by an equation of the form n = a+ b log w (360-w), a being a constant, and b of the form c + cl log I, where c and d are constants. If the disc is considered to be under unit illumination when lighted by a standard stearine candle, burning 8*273 grm. of stearine per hour, at a distance of 4 m etres; that is, if I is taken to be 1 under these conditions, then, from the combination of the series of observations described in Papers I and II, with many others made since, it follows that the numerical value of n is determined with a very fair degree of accuracy to within at most three revolutions per second, and generally within one, from the equations n = 10*7 + 12*57 log I, for discs half white, half black, and n = -27*83+ (8*57 + 2*79 log I) log w (360 -w), when the angle of the white sector is w°.These two equations hold only for illuminations above 3*98, i.e. that given by the candle at 2 metres distance. For illuminations below 3*98, the two corresponding equations to be used are, for the w = 180° disc, n = 17*6+ 3*469 log I, and for discs with a white sector w, other than 180°, the equation n = -38*6+ (12*4+ 0*77 log I) log w (360-w)gives satisfactory values for white sectors larger than 60°, but not so consistent