(2) Raphanus, near R. maritimus. Growing near beaches in South Chile, and not infrequently represented in the stranded beach-drift by the pods, which in my experiments floated seven to ten days in sea-water, after drying some weeks.
(3) Franseria. A species common on the beaches of Valparaiso and Talcahuano. Its prickly fruits, after being kept six weeks, floated only two to four days. They are well suited for transport in birds’ plumage.
NOTE 72 (page [483])
The Southern Limit of the Mangrove Formation in Ecuador.
... The southern limit of the mangrove formation on the west coast of South America is usually placed at 4° S. lat.; but it is probable that the vicinity of Tumbez in lat. 3° 30ʹ S. would be more correct. Baron von Eggers would place it rather further to the north-east, near the frontier of Ecuador and Peru in lat. 3° 20ʹ S. I spent eight days in the locality last named and saw no evidence of the beginning of the mangrove-formation.
NOTE 73 (page [495])
Additional Note on the Temperature of the Dry Coast of Ecuador between Puna Island and the Equator.
... Baron von Eggers gives the mean annual temperature for El Recreo, about half a degree south of the equator, at 75° F., which is near that of Rio de Janeiro in lat 23° S. on the east coast of the continent. Mr. F. P. Walker has kindly given me the results of temperature-observations covering a period of ten years, taken in the room for testing cables at Santa Elena Point (2° 10ʹ S.), usually about 6·30 a.m. The range of the monthly means was 71° F. (August) to 79·1° (March), and the mean for the year was 74·8°. In that locality a typical daily range would be 65° to 80°; and Mr. Walker believes that a minimum of 59° has been recorded.
NOTE 74 (page [495])
Observations on the Temperature of the Humboldt Current from Antofagasta Northward, between January and March, 1904 (Fahrenheit scale)
The observations were usually taken at the anchorages, but in some places, as at Ancon and Puerto Bolivar, they were taken from a boat outside the roadstead.
If we wish to ascertain how the Humboldt Current retains its cool temperature as it advances through the tropics to the equator, a glance at the following table will show that the surface-temperatures can aid us but slightly, since they do not vary in accordance with the latitude, a subject further discussed below. We can, however, obtain some valuable indications from the deeper temperatures. Let us take for instance the plane of 60°. Whilst south of Ancon (lat. 11° 45ʹ S.) it was rarely deeper than four fathoms, north of this latitude it descends rapidly, being probably about ten fathoms down at Salaverri and Eten and about twenty fathoms deep at Payta, in latitude 5° S., where the Humboldt Current leaves the coast. Within the Gulf of Guayaquil it is probable that the plane of 60° would descend to nearer thirty fathoms, the region being outside the influence of the current.
Some interesting facts are also elicited from the variation of the surface-temperatures. When we were coasting along at a distance of five or six miles from shore the readings were fairly constant from hour to hour varying only a degree or so. But nearer the land, for instance, about two or three miles away, the variation from hour to hour amounted to two or three degrees, whilst within the limits of the anchorages, a mile and less from the coast, the change from hour to hour amounted to three or four degrees. Nor was there any uniformity at the same hour over the surface of a roadstead. The temperature would often rise or fall a degree every few boat-lengths. Sometimes the inshore water was the coolest and sometimes it was the warmest. Thus at Iquique the inshore water was three degrees warmer than the water half a mile out, whilst at Mollendo, when the temperature one-third of a mile off the shore was 70°, it was 63° close to the rocky coast. The same thing was exhibited at Pisagua, where the surface-water two miles out at sea was 61°, whilst close inshore at the anchorage it was 58°. It was evident that there was a considerable intermingling of the warmer surface and the colder, deeper waters on the coasts of Chile and Peru. This was particularly noticeable on a rocky, steep-to coast, or where there was an uneven bottom. At some places, indeed, the warm upper layer did not exist, the cold water welling up all along the coast. This was especially the case between the 22nd and 19th parallels of latitude, a tract of coast in which lie Tocopilla, Iquique, and Pisagua, and probably the coolest part of the sea-border at this season of the year.