It were bootless to follow our erudite Professor through all the various topics which engage the remaining part of his time while in and around Boston. In the dead of winter, when he could make few or no personal observations upon the geology, or soils of the neighborhood, he draws upon the various surveys, and authors, which he found in abundant number around him; and his various disquisitions, and dissertations, of which we have many, are still taken from the statistics, and official reports of the Commonwealth, to neither of which does he give the slightest credit. In the large amount of this material which he has so unblnshingly appropriated, we are reminded of that prince of critics, old John Dryden, who, finding a plagiarist of remarkable dimensions, exclaimed in his indignation, "that instead of picking here, and stealing there, like a common literary mouser, he pounced down and appropriated the spoils of others with all the audacity of a conqueror!" Indeed, we think he shows a better taste in the selection of his subjects while at Boston, than at any other point in his travels; and possibly, had he remained some months longer, he might have informed himself into quite a tolerable train of extract.

But we doubt whether, after all, they could have indicated other than the researches and notices of a remarkably small man. Had nature favored him with a modicum of the discrimination and modesty of a Lyell, and his own judgment furnished him with an equal disposition to investigate for himself upon the broad surface of our country, and to an equal extent that his own vanity and self-complacency permitted him to appropriate the not exceedingly well selected subjects from the toils of others, his own countrymen would be better instructed, and our respect for his rectitude of motive be enhanced.

His stories, by way of illustrating his conclusions, are absurd and pointless; his pick-ings, of matter poured forth in the bitterness of party feeling, out of newspapers, are mischevious waggery of others, are so many Munchausens which prey upon his credulity. That he makes some sensible and proper remarks, and arrives at occasional right conclusions, is not denied; but the carping spirit in which he generally discusses his subjects, and the deprecatory approbation which he yields when he can no longer withhold it, are a lively testimony to the grudging temper in which he looks upon us and our country. We can afford to be criticised - abused, even - for we confess to many and frequent delinquencies - when necessary, and done with smartness and discrimination from the salient points of one's own observation; indeed a little wholesome castigation to our National self-complacency may be at times most wholesomely administered; but we choose that it be done by the hand of a master. For the donkey-like reproof of a quack and a bungler, we have no relish.

We sat down to these volumes of Professor Johnston with the anticipation that in a man of pretended attainments in our own favorite science of agriculture, and its attendant pursuits, a traveler to some extent in the way of his profession, on the European Continent, and now in the maturity of his intellect and the vigor of his mind, coming to a country, certainly not without interest to an intelligent investigator of the natural sciences, to make his professional observations, and to select objects of interest and novelty for the instruction of his countrymen, we should find something both rich and rare. A reading of his books has, to be sure, discovered to us much in either; but we have risen from our search with the sorrowing conviction that what he has chronicled as rare, is not particularly rich, and whatever he has recorded as rich is not at all rare. Had he confined himself simply to his professional, labors and investigations,and they been really labors and investigations of his own, we doubt not he could have made up a volume of matter both interesting and instructive. In the United States was a fresh mine of vast resource, inviting both his chemical and his agricultural exploration.

He chose to neglect these, to become philosopher, politician, and political economist; and on subjects upon which vastly abler foreigners than himself have preserved a discreet silence, or written but moderately well, he has poured out his half-pledged opinions with the flippancy, garrulity and emptiness of a Trollope, and a Fidler. A parting specimen we give in our traveler's visit to Springfield, when speaking of the national armory at that place. "Springfield, from its position as the place of meeting of so many railways, is remarkably well chosen as the site of a national arsenal. Weapons for 300,000 men can, upon the first telegraphic signal, be dispatched either up the Connecticut towards Lower Canada, through Albany towards the Lakes, or to the Atlantic shores northward by Boston, or southward by New-York." A school boy might have said this very prettily. But it so happens that this national armory was established by our government upwards of half a century ago, when Springfield was an obscure inland town, off from navigable waters, or easy communication, and for the very reason that it was so, and a long generation before either railways or telegraphs were known! The wisdom of Congress in this matter is therefore, as applied by our Professor, altogether apocryphal.

The accident that Springfield lay in a central position, and on the best line of construction, made that town "the place of meeting of so many railways." The railways met the arsenal - not the arsenal the railways. Our Professor's sagacity in this matter equals that of his philosophic prototype, who acknowledged the great kindness of Providence in making the navigable rivers run by the great towns and cities, that the people who dwelt there might be accommodated in their shipping facilities!

But we tire of quotations, which might, of like character, be almost indefinitely extended from the two volumes before us. On the 26th March, Mr. Johnston left Boston for the valley of the Connecticut, visited Springfield, Northampton, Amherst, and Greenfield. "Greenfield is a small town, new, straggling, and unfinished, as all these country towns are." These Connecticut valley towns, we believe, are about two hundred years old! For the first time he now appears to be awake to the beautiful scenery of our country. In this jaunt he is received by every one on whom he calls, with courtesy and marked attention, and condescends to give a trifling credit for it. His manners rend with the season, and probably had he sojourned during the summer among the Yankees, he might have become as agreeable a man as an unpolished manner, and an uncouth provincial accent in his language, would have permitted. He dashes on over the railway to Albany, stops a day there, and goes down the Hudson to Poughkeepsic in a steamboat, is disappointed in its scenery - sees nothing to admire, and, in a car ride along the banks of the river to New-York, makes up his mind that he "was not in a condition to form an adequate idea of what its beauties in its summer garb really are!"