San Juan d’Ulloa.—­The following facts, relative to the attack on San Juan d’Ulloa by the French, in 1838, are drawn principally from the report of a French engineer officer who was one of the expedition.

The French fleet consisted of four ships, carrying one hundred and eighty-eight guns, two armed steamboats, and two bomb-ketches with four large mortars.  The whole number of guns, of whatever description, found in the fort was one hundred and eighty-seven; a large portion of these, however, were for land defence. (Fig. 37.)

When the French vessels were towed into the position selected for the attack, “it was lucky for us,” says the French officer in his report, “that the Mexicans did not disturb this operation, which lasted nearly two hours, and that they permitted us to commence the fire.”  “We were exposed to the fire of one twenty-four-pounder, five sixteen-pounders, seven twelve-pounders, one eight-pounder, and five eighteen-pounder carronades—­in all nineteen pieces only.”  If these be converted into equivalent twenty-four-pounders, in proportion to the weight of the balls, the whole nineteen guns will be less than twelve twenty-four pounders.  This estimate is much too great, for it allows three eight-pounders to be equal to one twenty-four-pounder, and each of the eighteen-pounder carronades to be three quarters the power of a long twenty-four-pounder; whereas, at the distance at which the parties were engaged, these small pieces were nearly harmless.  Two of the powder magazines, from not being bomb-proof, were blown up during the engagement, by which three of the nineteen guns on the water front of the castle were dismounted; thus reducing the land force to an equivalent of ten twenty-four-pounders.  The other sixteen guns were still effective when abandoned by the Mexicans.  The cannonade and bombardment continued about six hours, eight thousand two hundred and fifty shot and shells being fired at the fort by the French.  The principal injury received by the work was from the explosion of the powder magazine.  But very few guns were dismounted by the fire of the French ships, and only three of these on the water front.  The details of the condition of the ships and fort are given in the report of the French officer,[22] but it is unnecessary to repeat them here.

[Footnote 22:  Vide also House Doc.  No. 206, twenty-sixth Congress, first session]

In general terms, it appears from the above-mentioned report, that the number of guns actually brought into action by the floating force, (counting only one broadside of the ship,) amounted to ninety-four guns, besides four heavy sea-mortars; that the whole number so employed in the fort was only nineteen, including the smallest calibres; that these guns were generally so small and inefficient, that their balls would not enter the sides of the ordinary attacking frigates; the principal injury sustained by the castle was produced