The expenses of the canal of Languedoc, averaged on its whole distance, were 13,889 dollars per mile; those of Clyde, 25,714 dollars, nearly double. The locks of the former are more than one to every two miles: those of the latter, more than one to every mile ; nearer double than the sum of their expenses. The surface of the reservoirs to the latter is over the proportion of distance to the former ; so are the aqueduct bridges and bankings also. But the width of the canal of Clyde is only fifty-six feet, probably only half the width of that of Languedoc, but it is one-third deeper. It is probable the same labour in the former cost three to two of the latter. The latter was completed more than a century before the former. As the price of labour gradually rises with the multiplication of property, this will account for the difference. The price of labour in the United States is still more disproportioned.

We have the expense of the fourth mile of the canal of Clyde, which includes ten locks, and a fine aqueduct bridge, given separate, 80,000 dollars. From these data we may presume the thirty-nine locks with four miles of the canal, cost about one-third the whole sum. These, with the reservoirs and the bankings through mossy ground, &c. probably one half. This would leave its cost, when made through good and level ground, at about 14,500 dollars per mile. This calculation makes locks enormously expensive; probably three locks would cost more than one half of canal in good ground.

Of the canal of Languedoc-it would be but a rude conjecture, in me, to say what distance of the canal, in good ground, the labour which was bestowed on its reservoir of 595 acres would make. However, to favour my calculation, I will presume on the probability that the extra labour which that canal required, in its reservoirs, tunnels, &c. more than it is probable the proposed one will, is equal to twenty miles, which added to one hundred and eighty, makes it equal to two hundred miles or the supposed length of the latter. This will leave their difference only in their respective number of locks. Through my ignorance in the art of canalling (that which has involved me in so many probabilities) I am wholly unable to make a calculation on the number of locks which the Genesee Canal may require ; but to further the argument I will presume 26.* This gives a difference of four to one, or 78 locks for their whole difference.

If we can presume on the excess of expense in locks, reservoirs, and bankings in the canal of Clyde; over the one proposed, together with American ingenuity in the invention and use of labour-saving machines, for making an equivalent to the excess in the price of labour in the United States, we may venture to lay its price at the same rate-or, which is nearly the same, to double the price of that of Languedoc, and allow its distance at 200 miles, we shall find it to cost something more than five millons ; to put it in round numbers, say 6,000,000 dollars. This will average 30,000 dollars per mile; or 93 dollars 75 cents per rod.

Were the executive of our government to instruct its foreign ministers and agents to collect every information from authors, engineers, and plans of foreign canals, which the old world affords, we could doubtless profit largely at their expense in our infant undertakings.

Its advantages are too obvious to admit of a question. Of these, I shall only particularise two or three articles and glance at a few others.

In its tendency to improve and foster our natural resources, the effect which it would have on the article of pot-ash alone, would, in time, be sufficient to pay more than the expenses of the canal. I presume the following calculation will demonstrate the proposition.

At present, pot-ash is made as far inland as Batavia. The heavy charges on land transport would prevent it from ever extending as much further as to Niagara, consequently the waste timber of all our forests to the west of that, must be lost to the commerce of the United States. The effects of the canal in encouraging the manufactory of pot-ash, may be calculated to commence at the foot of Lake Erie. The American shores of that lake are about 300 miles; the shore of the straits of Detroit through Lake St. Clair to Lake Huron probably 80 miles; Lake Huron's shore, say 320 miles; the whole circumference of Lake Michigan, about 600 ; total, thirteen hundred miles, without taking Lake Superior into account.

Allow this range fifty miles width for the greatest distance of land carriage to the several landings on these shores. This gives 65,000 square miles, or 41,600,000 acres in this tract.

One acre well timbered with hard wood will afford fifty bushels of ashes-from six to seven hundred bushels field ashes, make a ton of pot-ash, or fourteen acres-but allowing reserves for woodland, waste and neglect in collecting and saving ashes, &c. say that only one ton to every fifty acres shall be brought to market, this would give 832,000 tons.

Pot-ash can be manufactured, taken from the works to the country merchants, twenty or thirty miles, and afforded at 100 dollars per ton. The charges of transport from this village to New-York are about thirty-five dollars. To aid my calculation, I will presume on this for the average price of freight from the lakes through the canal. Its present price in New-York is 220 dollars per ton. Its average price in that market for ten years past is full 150 dollars. This will give the manufacturer and country merchant fifteen dollars profit. Allow the shipping merchant for his profits ten dollars, making twenty-five dollars per ton for the sum of net profits to American citizens. I consider this calculation to be within fact averaged on the whole quantity of pot-ash for the term past. We may at least rely on it for the future, when we consider the improvements yet to be made in the manufactory of that article, of which it is susceptible, and for which we already have a certainty in Alex. M'Nitt's patent therefore. So far as his patent has been essayed, it has rendered pot-ash standard first sort. With the improvement of its quality we may calculate on the enhancement of its price. Taking for granted the twenty-five dollars on 832,000 tons, gives 20,800,000 dollars for the amount of net profits, a sum which perhaps cannot otherwise be realized by the citizens of the United States. To this sum add the advance value on this article along the shores of the canal, and it will make an amount equal to four times the conjectured cost of it.

Another consideration offers to view-to the New-York price of 150 dollars, add American freightage to Europe, and call the price 200 dollars per ton. The gross amount of 832,000 tons would be 166,400,000 dollars in exports answering our merchants for their remittances equal to cash.

These calculations also serve to give us some ideas of the resources of capital we have in our forests.

It is singular that this valuable article of commerce is not made in any considerable quantity to the south of this state. From the Philadelphia price current, I presume their merchants give it no encouragement. It might be attended with advantage in the other middle states, and particularly in the western. It could be transported from Pittsburgh to New Orleans for twenty dollars per ton. By its serving as ballast freight to cotton, it could be exported from thence for nearly the same charges as from the Atlantic ports.

HERCULES.