A few days since, we called public attention to the singular conduct of James G. Wilkins, justice of the peace for the "Cape Horn" district, in this county, in discharging without trial a man named Parker, who was, as we still think, seriously implicated in the mysterious death of an old man named Summerfield, who, our readers will probably remember, met so tragical an end on the line of the Central Pacific Railroad, in the month of October last. We have now to record another bold outrage on public justice, in connection with the same affair. The grand jury of Placer County has just adjourned, without finding any bill against the person named above. Not only did they refuse to find a true bill, or to make any presentment, but they went one step further toward the exoneration of the offender: they specially _ignored_ the indictment which our district attorney deemed it his duty to present. The main facts in relation to the arrest and subsequent discharge of Parker may be summed up in few words: It appears that, about the last of October, one Gregory Summerfield, an old man nearly seventy years of age, in company with Parker, took passage for Chicago, _via_ the Pacific Railroad, and about the middle of the afternoon reached the neighborhood of Cape Horn, in this county. Nothing of any special importance seems to have attracted the attention of any of the passengers toward these persons until a few moments before passing the dangerous curve in the track, overlooking the North Fork of the American River, at the place called Cape Horn. As our readers are aware, the road at this point skirts a precipice, with rocky perpendicular sides, extending to the bed of the stream, nearly seventeen hundred feet below. Before passing the curve, Parker was heard to comment upon the sublimity of the scenery they were approaching, and finally requested the old man to leave the car and stand upon the open platform, in order to obtain a better view of the tremendous chasm and the mountains just beyond. The two men left the car, and a moment afterwards a cry of horror was heard by all the passengers, and the old man was observed to fall at least one thousand feet upon the crags below. The train was stopped for a few moments, but, fearful of a collision if any considerable length of time should be lost in an unavailing search for the mangled remains, it soon moved on again, and proceeded as swiftly as possible to the next station. There the miscreant Parker was arrested, and conveyed to the office of the nearest justice of the peace for examination. We understand that he refused to give any detailed account of the transaction, only that "the deceased either fell or was thrown off from the moving train."