38 FROM SAN LUIS TO EOSARIO. 



interruption of curious people, which, hy the way, was always an important consideration, for the 

 gauclios universally wear spurs and sheath-knives, and it was difficult to make them understand 

 that these affected the magnets. Sometimes they would come close to where I was at work, 

 with hidden knives, merely for the purpose of seeing whether I could detect their presence by 

 the action of the magnet. Near some of the lagunas, we had passed occasional trees that would 

 have answered hut for the annoyance of raosquitos. At length this one jiresented itself, at some 

 distance to the right of the road, and, allowing the mules to go on, I galloped oif, and found it 

 the most appropriate place I had seen since leaving Chile. To hurry on and stop the party was 

 my next step ; and as fortunately there was a pond of tolerable water near, we had all we could 

 desire. This peje tree, with three or four algarroba companions, stands on a little knoll ; and 

 what was particularly delightful about it was^ that although the mosquitos were swarming at 

 the distance of fifty yards in every direction from it, there were only a few under it. 



Here, in its delightful shade, I was able to conclude work before sunset, and be off again in 

 time to avoid an attack from flies, which, with the falling shades of evening, were losing 

 all respect for the tree, and came swarming around us. We had the satisfaction, however, 

 before finally leaving, to see them slaughtered right and left, by hundreds of mosquito-hawks 

 (dragon-flies) that appeared to have sprung into existence by miracle, as we had before only 

 seen an occasional straggler. 



The tree was about two feet in diameter, forty feet high, and had fifty feet spread. Its limbs 

 were closely interlaced, and filled with nests, principally of the scissor-bird, common to the 

 country from Mendoza to Eosario. This is about the size and color of the mocking-bird, and 

 gets its name from two long tail-feathers, resembling the blades of a pair of scissors. 



As this was one of the most level parts of the pampa we had passed, I had the curiosity to 

 set up the theodolite, and see how far it departed from a perfect plane. Setting the horizontal 

 wire on the horizon in one direction, I turned the instrument through the circle, and found five 

 minutes' depression at every point except north, where, by the intervention of a knoll, it was 

 only two minutes and thirty seconds, and at northeast four minutes; so that an observation 

 with the natural horizon, in the most unfavorable direction, when corrected for dip, would have 

 been only two minutes and a half in error. 



It may seem ridiculous to attach so much importance to a single tree, but it really is not so. 

 The traveller on the jjampa frequently looks in vain for one under whose shade to pass the 

 siesta, and with whose wood to cook his beef. He may discern one, apparently a long way off, 

 that offers, as he thinks, every requisite ; but, on nearing it, he finds that what looked stately 

 in the distance is a mere shrub. These disappointments are of continual occurrence. One of 

 the places where we j^assed the siesta had so very little shade to recommend it, that I urged the 

 arriero to go farther; but he refused, telling me I ought to give "gracias a Dios" for even that 

 much ; and after we were farther advanced over the pampa, I found he was right. 



Travelled about sixteen miles farther on the 29th, and stopped near the little village of Sala- 

 dillo. During the night there was a very heavy dew ; weather clear, and, for the season, cold. 

 Thermometer at 4.30 a. m. (December 30) 56° Fahrenheit. 



Decemher 30. — Set out at daylight, and at 5 o'clock entered the town of "Saladillo de Rui 

 Diaz." It is partially surrounded by walls and ditches, and consists of some two hundred 

 thatched adobe houses and huts, not one of which is decent-in appearance. It has a plaza and 

 barrack, where there were about eighty soldiers quartered, but has no church, and, with greater 

 advantages than any other town along the road, is perhaps the most wretched looking. The 

 three roads from the westward, and that from Cordova, all i)ass here, and, to judge from what 

 we saw, there must be a great deal of traffic and travel at this point. The country was alive 

 with trains of ox-carts and mules, going or coming. There were in sight about a hundred 

 carts, and altogether it was a very enlivening scene, reminding us, in an unmistakable manner, 

 that we were approaching civilization; I'or which, to use the arriero's expression, I gave "gra- 

 cias ii Dios y Maria Santisima." The creaking wheels of the ox-carts, heard far and near, the 



