Art Mu tier*—Duneanson’a Last Picture.During a recent visit to Duneanion's studio wo found ho had just finished a now picture, entitled The Rainbow,'' a oompoeition of studiesfrom nature, which we regard m the moat oompUte and artistic painting ho baa yet prodoood.The piotnro la a boautiful landscape— the foreground representing low ondulat.bg land, with daw soil, partially washed by raine, through which flow several small rivulets. On the right are riling ground and a hill, with a dwelling peeping out from the foliage; in the •enter a lake, skirted by occasional heaehei; an upon plain beyond: another house embowered among trees, and in the diitanoo bine hills or monntalos stretching far away, on one of wbloh the setting aun falls, lighting it up with a golden glory that la as finely oonoeived as executed.The season ii supposed to bo September, and the hour six of the afternoon. A shower has just passed over, and the olouds are still visiblo at the right; while ever th« front of the pioture are the two forim'nt of a beautiful rain-buw.We hare oar own idea of the rainbow, and of the propriety of any artist, however gifted, attempting to catch Its subtle hues or reproduce its unique semblance on hisoanvas; but still we can not deny that Dunoanson has .ucccoded very well in this most difficult endeavor. Hie whole painting Is most creditable, and muit increase the reputation he has earned.All the details are finished, and the painting has more of the true art atmosphere in and about It than we remember to have no-tiood in any of his previous works. About the landscape lies a dreamy, poetic languor that is charming to the seme and rofresnlng to the spirit, and we felt ourselves sighing for such an Aroadio as we sat musing before “The Rainbow in a bleak and wintry afternoon.Every feature in lita piotnro is a study from nature, and tho whole Is but a transcript of fragment* selected here and there, most of them from socnory in this vicinity. The landscape reminds one of Italy, as doea much of the scenery hereabout, and no one can gaze at it long without experiencing a sympathy with its quiet beauty and delicious repose.We have written crudely, bocauso hurriedly, of “The Rainbow, but having no leisure to ■ay more, we would reootnmend connoisseurs to pay it a visit, which It amply merits.