The result of the astronomical observations, and some of the observations themselves, will be found in the Astronomical Appendix.

Through the courtesy of Major Paul, the commanding officer at Ringgold Barracks, the observatory was placed within the enclosure of the military grounds, and west of the officers' quarters. The height of this point above the sea, by the barometer, is 521 feet; the magnetic dip 52° 27', and the declination 9° 15' east. The observatory was 70 feet above the bed of the river, so that the river-bed is 451 feet above the sea at this point. The distance to the sea, measured by the sinuosities of the river, is 241 miles; the direct measurement only 75 miles. If the river had a direct run to the level of the sea, it would have a fall of six feet to the mile, and would probably empty itself in dry seasons, so that the tortuous course of the river, so vexatious to the traveller, is of importance in an economical point of view. My observations embraced three summer months at Ringgold Barracks, during which time the excessive heat was tempered by the sea-breeze, which was felt here daily with great force. Dr. Brown, assistant surgeon United States army, stationed at this post, has kindly furnished me with the meteorological journal kept by him for several years, and I give it in place of my own, as it extends over a much greater space of time, and will, therefore, afford a much more comprehensive view of the climate. It may, also, be taken as a fair type of the climate of that region of country which extends from Brownsville to Eagle Pass. It will be seen from this and subsequent records how dry the country becomes as we go towards the centre of the continent.

The beautiful town of Roma, 16 miles above Ringgold Barracks, is the present head of steamboat navigation; it is built upon a high bluff of yellowish sandstone, containing ferruginous nodules. When I visited this small town, I was at a loss to know how such fine residences and warehouses, all recently built, could be sustained by its trade; but being the guest of the owner of one of these large establishments, I did not think proper to be very inquisitive. At night, when I went out to take my observations for the determination of the latitude and longitude of

the place, I found that the mercury of the artificial horizon was very tremulous, notwithstanding the calmness of the night. Not being able to overcome the difficulty, or ascertain its cause, I

put up my instruments and returned to my quarters. On the way I encountered a long train of mules, heavily laden, directed towards the Mexican side of the river. The motion of the animals caused the disturbance of the mercury, and their rich burden of contraband goods, intended for the Mexican market, explained the commercial prosperity of the town. As might reasonably be expected in any country where the duties on foreign goods amount almost to prohibition, smuggling ceases to be a crime, but is identified with the best part of the population, and connects itself with the romance and legends of the frontier.

Between Roma and Ringgold Barracks there is much excellent land susceptible of irrigation, and both banks of the river are thickly settled with Mexicans. There are many Americans in this part of the country engaged in trade, but I cannot, at this moment, recall to mind a single one engaged in agricultural pursuits. Sugar cane will grow on this part of the river, but the land is rather too elevated for that plant to be grown with profit. Indian corn is the staple product, and when extradition laws are enacted and enforced, and the Indians who periodically plunder the country are exterminated, the rearing of cattle will be followed with advantage.

After studying the character and habits of that class of Indians called wild Indians, and bearing in mind the mild and humane government extended over them by the missionaries of the Church of Rome, without producing any results, I have come to the deliberate conclusion that civilization must consent to halt when in view of the Indian camp, or the wild Indians must be exterminated. Nothing could exceed the judgment, perseverance, and humanity with which the various orders of the Catholic Church have pursued, for three hundred years, the work of redemption among these savages; but at the very moment when Christianity appeared most likely to triumph, the savages turned upon their benefactors and swept them from the face of the

earth. There are distinct races among the Indians as among the white men, and before the advent of Christianity they were divided into semi-civilized and wild races. The semi-civilized then, as now, cultivated the soil, lived in houses, some three stories high, and kept faith with each other, and it is among these that Christianity has made any permanent impression. The wild Indians were then, as they are now, at perpetual war with them, leading a nomadic life, defying all restraint, and faithless in the performance of their promises. They have but two settled principles of action-to kill the defenceless and avoid collision with a superior or equal force. In the early stages of my experience with these Indians, I was inclined to believe them maltreated, and to consider their present reckless condition the result of the encroachments of the white people upon their rights; but such is not the case-experience proved to me that no amount of forbearance or kindness could eradicate or essentially modify the predominant savage element of character. The semi-civilized Indians form, however, much the larger class of Indians on the Mexican frontier. Indeed, nine-tenths of the population of all Mexico are Indians, or have the blood of Indians coursing in their veins. A pure white, of unadulterated Spanish blood, is rather the exception than the rule. I do not know how far the effects of the sun can be considered to have bronzed the complexion, but it seemed to me the proportion of pure white in the northern States of Mexico bordering on the boundary, was greater than in southern Mexico, always excepting the cities of Jalapa, Puebla, and Mexico.

One of the most important duties of our survey was to determine to which side the islands in the Rio Bravo belonged. For this purpose it was agreed between the Mexican commissioner and myself to sound the river on each side of every island, and the centre of the deepest channel should be the boundary line. From the mouth of the river to Ringgold Barracks there are eleven islands, marked on the map from 1 to 11, commencing at the mouth, and this order of numbering the islands is observed until we reach the parallel of 31° 47', where the boundary leaves the river. The sheets of the boundary, on a scale of doo, are numbered from 1 to 54, No. 1 being the mouth of the Rio Grande, and the numbers progressing regularly from the Gulf of Mexico to the Pacific. The islands are numbered on these sheets to indicate their geographical position, but they are represented also on separate sheets on a scale of doo, to show their topographical and hydrographic details, and to exhibit upon what data they have been allotted to the United States or to Mexico.

1 600009

1 6000

Up to Ringgold Barracks these islands are of little value, but above that they are of more importance. Islands Nos. 12 and 13, between Ringgold Barracks and Roma, both fall to the United States. No. 13, called on the maps Beaver island, divides the waters of the river into three parts, and the channel which lies nearest to the Mexican shore is so narrow that steamers can with difficulty pass through it, yet the branches are, by reason of their shallowness, wholly impassable for them. An attempt was made by the Mexican local authorities to arrest the steamboat in its passage through this channel, but not only the survey, but the actual experience of the navigator, proved the narrow one to be the true channel, and consequently the boundary between the two countries. The allotment of all the islands was made upon the condition of things as they existed when the boundary was agreed upon. The channel of the river may change and throw an island once on the Mexican side to the American, and vice versa, but neither the Mexican commissioner nor myself could provide against such a contingency, none having been anticipated in the treaty.

We however agreed, as far as that agreement may be worth anything, that in case the channel Vol. I-9

of the river changed, the right of navigation through the new channel should remain unimpaired to both countries, but the jurisdiction of the land must remain as we had arranged.

Five miles above Roma, and opposite Mier, there is a large island called Los Adjuntas, which was awarded to the Mexican side. At present the channel is between the island and the American shore. Formerly the channel was very nearly equally divided on either side of the island, but during the occupation of Mier by the American troops a temporary causeway was constructed of loose stone, to enable the cavalry to cross their horses to the island for the purpose of grazing. This causeway, now nearly washed away, has given a permanent direction to the channel which rules the island out of our territory. At the lower end of the Los Adjuntas and on the Mexican side are tepid baths, luxurious for the robust, and valuable for a certain class of diseases. The springs which supply these natural baths are near them, and are supposed to possess medicinal virtues of a high order. They were supposed to be sulphur springs, but analyses of the water which I placed in the hands of Dr. Easter detected no trace of sulphuretted hydrogen. The zoological character of the rocks from Reynosa, where the cretaceous formation was first noticed, up to Las Moras, a distance measured on the parallel of latitude of 144 miles, is much the same, while they differ in their lithological character. If any difference is to be noted in the zoological character of these rocks it is in the exposure, just above Roma, at the foot of the island of Las Adjuntas, and at several other localities in the neighborhood, of banks of fossil oyster-shells of great size, some of them measuring 18 inches in length.

*

I have noted at Roma the occurrence of sandstone studded with nodules of ferruginous iron. Throughout the section between the San Juan river and Loredo, septaria and strata of yellowish and green sandstone frequently cocur. Often the nodules of more durable substance project beyond the weather-worn surface of the softer sandstone, producing picturesque appearances. The town of Mier, famed in the history of the war of independence of Texas, stands upon the Alamo river, four miles back from the Rio Grande, contains about 700 inhabitants, and is now chiefly noted for the superior quality of the blanket manufactured there. It was an important point during the war with Mexico, being the point where the road to Monterey diverges from the Rio Bravo, and where the supplies for the invading army were transferred from water to land transportation. From Mier upwards, the course of the river is more nearly north and south, and less winding in its course. The banks on either side become more abrupt and rocky, and for the first time in ascending we find a rocky bottom.

Forty-six miles above Roma, measured by the river, is Bellville, the trading establishment of a hospitable and enterprising gentleman who has built himself a warehouse something after the fashion of old feudal castles—not for the purpose of ornament, but for defence against the Indians

*The following is the result of the quantitative analyses by John D. Easter. The whole quantity of solid matter was 0.6763 per cent., consisting of—