any risk to the sub-depot which you have been ordered to establish or without too much delay in completing its defenses. The manner in which this is to be accomplished and whether you will lead the party in person or designate some other officer to do so I leave with yourself to determine. The town once taken, it must be held as one of the steps toward the Rio Grande, and measures must at once be taken after that event to gather in wheat, flour, &c., from Sonora for the use of our troops. I inclose for your information some notes of the route by the way of the San Pedro, which if followed you will attack the town in reverse. A feint should perhaps be made along the route recently attempted by Captain Calloway, but I suggest that the real attack should be made by a party moving light without knapsacks, saddle-bags, great-coast, or any incumbrance, but arms, ammunition, provisions for wounded men, pemmican, bread, and forage, via Fort Breckinridge, up the San Pedro to the stage road, and in on that to Tucson. The side of the town next to this approach is exposed. The other side next to the Pima Villages by the route from Picacho is cut up by fields, gardens, corrals, &c., with live fences, making it difficult for men and horses to get up tot the houses themselves. If you take the two howitzers, they must be well supported by infantry. Having made your feint by moving a force over the route recently taken by Calloway, would it not be well to march the force destined to move via the San Pedro by night - at all events the first night? Have your sabers very sharp, that they may readily cut through clothing. Cavalry recently mounted on California horses cannot use any kind of fire-arms with success. The men should practice dismounting to fight on foot a great deal. If a rush is made by Texans on horse-back with revolvers upon your cavalry while mounted, if the sabers are sharp I would recommend closing in with them as quick as thought. The cold steel will win against the pistol. If they fly, follow with the pistol, but with our men well kept together and well in hand, or they will not succeed. In closing with cavalry against cavalry and in hand-to-hand encounters on horseback, it si well to get your enemy in your power by cutting off his reins, killing his horse, &c. If your cavalry hapen to be on foot and the Texans happen to be on foot and attempt to make a rush upon your men with revolvers, as is their custom, teach your men to use their fire-arms until the enemy is about to close, then to draw the saber and rush upon him with the speed of lightning. If he run, use the pistol until the shots are exhausted and then the carbine. It is my opinion that a judicious use of the saber on foot or on horseback will tell very much in your favor. Pray teach your men not to despise their enemy. Thsoe men who they go to encounter are determined men and will fight with desperation. You must be sure to take or send men enough to overpower them without a doubt. The Texans are fond of getting into an adobe town and of loop-holding the houses and there making a stand. In this event, by seizing some prominent row of buildings and by cutting your way from room to room until you get into the heart of the town, you gain all the advantages they themselves possessed. (At Taos, N. Mex., in February, 1847, our people cut holes through walls and threw, by hand, 12-pounder shells with fuses lighten in among the enemy. These cleared the place they occupied in a few moments.) In doing all this your wagons should be well guarded by infantry in the wagons, if necessary. In wagons infantry are very formidable, as it may seem. You can take any number of men you think necessary, provided the supplies at the sub-depot are left perfectly secure. If fully rely on your prudence and vigilance and resolution both en route and when you get your enemy under fire. Should you succeed you will hold the town and have your wounded cared for