The facilities which these Joint Stock Companies offer for the investment of capital, even of the smallest amount, the temptations which the prospect of large profits hold out, and the low interest obtained on national stock of every description, have attracted a vast body of capitalists, small and great, who have subscribed to these undertakings with the real intention of investment. But, on the other hand, there is a very extensive body of speculators who engage in them upon a large scale, without the most distant intention, and, indeed, without the ability, of paying up the amount of their shares. The loss which the latter class of persons may sustain would, probably, excite little commiseration, were it not for the consequences which must result to the former, should a revolution take place, and the market be inundated with the shares of these gambling speculators, who buy only to sell again. Effects would be produced which must be ruinous to a large proportion of the _bonâ fide_ subscribers. It may, therefore, be attended with some advantage to persons who really intend to make permanent investments of this nature, to state, in succinct and intelligible terms, the principal circumstances on which the efficiency and economy of railroads depend, so as to enable them, in some measure, to form a probable conjecture of the prospective advantages which the various projects hold out. In doing this, we shall endeavour, as much as possible, to confine our statements to simple facts and results, which can neither be denied nor disputed, leaving, for the most part, the inferences to which they lead to be deduced from them by others. It may be premised, that persons proposing to engage in any railroad speculation should obtain _first_ a table of _gradients_; that is, an account of all the acclivities upon the line from terminus to terminus, stating how many feet in a mile each incline rises or falls, and its length. _Secondly_, it would also be advantageous to have a statement of the lengths of the radii of the different _curves_ as well as the lengths of the curves themselves. _Thirdly_, an account of the actual intercourse which has taken place, for a given time, upon the turnpike road connecting the proposed termini, stating the number of coaches licensed, and the average number of passengers they carry; also as near an account of the transport of merchandise as may be obtained. The latter, however, is of less moment. An approximate estimate may be made of the intercourse in passengers, by allowing for each coach, upon each trip, half its licensed complement of load. _Fourthly_, the water communication by canal or otherwise between the places; and the amount of tonnage transported by it. With the information thus obtained, the following succinct maxims will be found useful:-- I.