3o8 



NATURE 



{July 25, 1889 



At Greenwich on July 28 

 Sun rises, 4h. 20m. ; souths, I2h. 6m. I4'03. ; daily decrease 

 of southing, i*3s. ; sets, igh. 53m.: right asc. on meridian, 

 8h, 3 1 -em. ; decl. 18° 54' N, Sidereal Time at Sunset, 

 i6h. 20m. 

 ^oon (New on July 28, oh.) rises, 4h. 27m. ; souths, 

 I2h. 33m. ; sets, 2oh. 28m. : right asc. on meridian, 

 8h. 58-4m. ; decl. 19° 51' N. 



Right asc. and declination 

 Planet. Rises. Souths. Sets. on meridian. 



h. m. h. m. h. m. h. m. o / 



Mercury.. 3 13 ... 11 19 ... 19 25 ... 7 44-6 ... 22 4 N. 

 Venus ... I I ... 8 56 ... 16 51 ... 5 20*5 ... 20 20 N. 

 Mars ... 3 10 ... II 18 ... 19 26 ... 7 43'i ... 22 20 N. 

 lupiter ... 17 38 ... 21 31 ... I 24*... 17 58*1 ... 23 22 S. 

 Saturn ... 5 46 ... 13 11 ... 20 36 ... 9 36 7 ... 15 27 N. 

 Uranus... 11 12 ... 16 42 ... 22 12 ... 13 8'6 ... 6 38 S. 

 Neptune.. 23 56*.. 7 45 ... 15 34 ... 4 9-8 ... 19 23 N. 

 * Indicates that the rising is that of the preceding evening and the 

 -setting that of the following morning. 

 July. h. 



28 ... 5 ... Mercury in conjunction with and 0° 14' south 

 of Mars. 



28 ... 20 ... Mercury at least distance from the Sun. 



29 ... 7 ... Saturn in conjunction with and 2° 16' south 



of the Moon. 



Variable Stars. 

 Star. R.A. Decl. 



h. m. . / h. m. 



Algol 3 I'o ... 40 32 N. ... Aug. 2, I so m 



R Ursas Majoris ... 10 36-8 ... 69 22 N , 3, M 



W Virginis 13 20*3 ... 2 48 S. ... July 31, 22 o m 



X Bootis 14 19-0 ... 16 50 N. ... Aug. 2, M 



R Camelopardalis. 14 26 'o ... 84 20 N. ... July 31, M 



5 Librae 14 55-1 ... 8 5 S. ...Aug. I, 2 32 w 



IT Coronae 15 137 ... 32 3 N. ... ,, 3, o 20 m 



U Ophiuchi 17 10-9 ... i 20 N. ... July 28, 23 17 m 



Aug. 3, o 2 /« 



X Sagittarii 17 40-6 .. 27 47 S. ... July 28, 23 o ^ 



Aug. 2, 3 o w 



U Sagittarii 18 25-6... 19 12 S. ...July 29, o oM 



U Aquilae 19 23-4 ... 7 16 S. ... ,, 31, 22 o m 



»7 Aquilae 19 46-8 ... o 43 N. ... Aug. 3, 3 o ^ 



T Vulpeculae ... 20 46-8 ... 27 50 N, ... July 31, 22 o M 



-I Cephei 22 2S'i ... 57 51 N. ... ,, 30, o o M 



M signifies maximum ; m minimum. 



Meteor-Shoiuers. 



R.A, Decl. 



Near S Andromedas 

 ,, 5 Cassiopeise ... 



The Perseids 



The Aqtiarids 



GEOGRAPHICAL NOTES. 



An expedition is about to start for the exploration of Central 

 Australia. Baron von Miiller is interesting himself in the 

 expedition, which will be under the command of the experi- 

 enced explorer, Mr. Tietkens, who will also look specially after 

 the botany and mineralogy. The point of departure will be 

 Alice Springs, on the central telegraph line, and the country 

 round Lake Amadeus will be carefully examined. 



It is reported from Brisbane, according to the Colonies and 

 India, that the Queensland Government has concluded an agree- 

 ment with Mr. A. Weston to lead an exploring party into the 

 almost untrodden recesses of the northern portion of the colony, 

 with a view to bringing to light scientific treasures supposed to 

 be hidden there. Mr. Weston has accepted the undivided 

 responsibility of leadership. Messrs. Broadbent and Bailey will 

 be associated with him, and will respectively discharge the 

 duties of collecting fauna and flora. The party will explore the 

 region lying to the north-west of Cairns, including the Bellenden 

 Ker Range and the shores of the volcanic lakes. It is also 

 thought that something may be heard of Leichardt's expedition, 

 traces of which are popularly supposed to be yet found in the 

 back country. Mr. Weston has refused to accept any pecuniary 

 assistance from the Government for his services. 



M. A. Delcommune, who has been exploring several of the 

 affluents of the Upper Congo, has arrived in Brussels. He has 



brought with him a valuable collection of African products, and 

 some 200 views on the Upper Congo. 



The news that Dr. Macgregor, the Administrator of British 

 New Guinea, has reached the summit of the Owen Stanley 

 Range is of much interest. Since Captain Owen Stanley dis- 

 covered the range, about forty- five years ago, various explorers 

 have attempted to scale it, but all have failed. The summit 

 reached by Dr. Macgregor is over 13,000 feet, and he reports 

 several peaks almost equal in height. As Dr. Macgregor is 

 a good botanist, his journey is likely to yield valuable scientific 

 results. 



Dr. Alfred Hettner, in a communication to the Verhand- 

 lungen of the Berlin Geographical Society (No. 6, 1889), on his 

 travels in Peru and Bolivia, gives the results of his observations 

 on Lake Titicaca, which are of some interest. The surface of 

 the lake, he states, has in the course of time been subject to 

 great changes of level. The proof of these changes is to be 

 found in the terraces around the lake. In a comparatively 

 recent geological period. Dr. Hettner believes, the level of the 

 lake must have been 20 metres higher than it is to-day, and the 

 lake must have spread over the great part of the plain which 

 now incloses it, perhaps as far as Lake Poopo. At a still earlier 

 period the level of the lake must have been 200 metres above 

 its present level, but between these stages, as many appearances 

 indicate, the lake must have sunk below that level. The 

 highest position of the lake-level is older than the glaciation of 

 the district, and contemporaneous with a period of strong 

 volcanic activity. The 20-metre high terraces may belong to 

 the ice-period. For the idea of a former submersion below the 

 sea Dr. Hettner can find no support ; at the same time, he 

 cannot altogether deny the possibility that at the time of the 

 200-metre terrace the lake may have had some connection with 

 the ocean. 



NITRATE OF SODA, AND THE NITRATE 

 COUNTRY.^ 



II. 



■XIZE will now consider the structure of the actual nitrate beds. 

 As before mentioned, there is no nitrate under the flat 

 Pampa ; but exactly where the first slopes of the coast range spring 

 out of the plain, there nitrate is found at a small but variable 

 distance below the surface. The width of the belt varies with 

 the slope of the hill, being greatest where the slope is least, and 

 the vertical height of the highest part of the bed appears to vary 

 from 100 to 1 20 feet above the plain. It is, however, most im- 

 portant to notice that the beds of nitrate follow the slope of the 

 Pampa, and not a lei'cl line. For instance, the northern extremity 

 of the Pampa is some hundreds of feet higher than the southern 

 portion, but the nitrate beds follow the spring of the hill from the 

 plain, throughout their whole extent. 



A very different sequence of beds lies under the slope of the 

 hills from those alternating layers of mud, sand, and gravel which 

 are found under the level Pampa. The surface covering of loose 

 dust and small stones, extending to a depth of only a few inches, 

 is locally known as chuca (see Fig. 3). This seems to be a 

 native word, but I have been unable to ascertain its meaning. 

 Below the chuca comes a very hard layer of earth and stones, 

 almost compacted into rock, from i to 2 feet thick, which is called 

 costra (Span, crust). Under this lies the caliche, or true 

 nitrate deposit. This is a bed of from i to 3 feet thick, usually of 

 a whitish crystalline structure, containing from 20 to 50 per cent, of 

 nitrate of soda, with a residuum made up chiefly of common salt 

 and earthy matter. Caliche is an Indian word, and may possibly 

 come from the Aymara word callachi, a shell, or skull. 



Passing through the caliche, a hard layer of stones and earth, 

 compacted with salt crystals, is usually encountered. The Spanish 

 workmen call this " congelo," because it is congealed or concreted 

 by the salt. 



After a foot or so of this, there comes finally a bed of soft, 

 loose, szueet earth, containing a few very small loose stones, 

 known as cova. I could not discover the signification of this 

 word ; but the whole method of working a nitrate bed turns round 

 the properties of the cova. 



A workman, with three or four chisel-pointed bars of iron, 



hence called a barretero, stands on the surface of the ground, 



and chips out a round hole, about a foot in diameter, down to 



the level of the cova. This hole is called a tiro, or charge for 



' Continued from p. i88. 



