February i, 1894] 



NATURE 



Ty^^l 



A Liquid Commutator for Sinusoidal Currents. 



My attention has been drawn to a note in Nature of 

 January ii (p. 253) which quotes from the Electrical World of 

 New Yorlc "a novel method of obtaining sinusoidal alternating 

 currents of very low frequency," described by Lieutenant F. 

 Jarvis Patten. The method is to make a pair of conducting 

 plates revolve in a vessel of liquid which also contains a pair of 

 lixed plates. This liquid commutator, however, is not new. It 

 was the subject of a joint patent taken out by Mr. C. G. Lamb 

 and myself a year and a half ago, and it was used in connection 

 with the magnetic curve-tracer in my British Association lec- 

 ture at Edinburgh on " Magnetic Induction,"' and again at the 

 Royal Society soiree last May. It has been, in fact, for some 

 time an item in Messrs. Nalder's catalogue of scientific appar- 

 atus. A description of it was published in the Electrician of 

 November 18, 1892. J. A. EwiNG. 



Engineering Laboratory, Cambridge, January 26. 



A Curiosity in Eggs. 



A COMMON "barn-door" hen, belonging to a neighbouring 

 farmer, recently laid an egg measuring 4^ inches in length by 7 

 inches in circumference ; weight 6 ounces. On this egg being 

 carefully broken a second perfect egg, with hard shell of 

 ordinary size (3 inches by 5i in circumference), was found float- 

 ing in the contents of the outer one. The contents of both eggs 

 appeared to be normal and healthy. This is surely a very 

 unusual occurrence. E. Brown. 



Further Barton, Cirencester, January 16. 



RICHARD SPRUCE, Ph.D., F.R.G.S. 



ALTHOUGH little known beyond a limited circle of 

 botanists and South American explorers, the sub- 

 ject of this notice was in many respects a remarkable 

 man, who, under more favourable circumstances, would 

 have acquired a wider reputation. He was the son of a 

 schoolmaster at the village of Ganthorpe, Yorkshire, 

 and at an early age showed a taste for botany, having 

 compiled a '' List of the Flora of the Malton District " 

 in 1837, when he was just twenty years old. For some 

 years he was teacher of mathematics at the Collegiate 

 School, York ; and during his holidays he explored Esk- 

 dale, Teesdale, Killarney, and other districts, paying 

 special attention to the mosses and hepatics, among 

 which he discovered many new species, which he de- 

 scribed in the Phytologist, the Transactions of the Botani- 

 cal Society of Edinburgh, and in the London Journal 

 of Botany. In 1845 he went to the Pyrenees, where he 

 spent ten months, chiefly devoted to his favourite 

 groups of plants, among which he discovered a large 

 number of new or rare species. These were fully described 

 in a paper published in the Annals and Magasi?te of 

 Natural History in 1849. 



The delicate state of his health requiring a warmer 

 and more equable climate than that of his native York- 

 shire, he decided, by the advice and with the assistance 

 of the late Sir William Hooker, to visit the Amazon 

 valley as a botanical collector, with the object, if possible, 

 of reaching the head waters of the Orinooko and the 

 eastern valleys of the Andes, districts whose riches had 

 been indicated by the explorations of Humboldt and 

 Bonpland at the beginning of the century, but which no 

 experienced botanical collector had since visited. In- 

 valuable assistance was also given by the late Mr. Ben- 

 tham, who undertook the great labour of dividing and 

 distributing the dried plants as they arrived in England, 

 and sending sets to those who subscribed for them, thus 

 'acting as an unpaid but most efficient agent. The same 

 eminent botanist described most of the new species of 

 flowering plants as they arrived, thus making known the 

 value of the collections, and ensuring the sale of the 

 whole of the specimens. 



In July, 1849, Mr. Spruce arrived at Para (where the 



NO. 1266, VOL. 49] 



present writer first made his acquaintance), and during 

 the succeeding fifteen years carried out successfully a 

 series of voyages and explorations in equatorial South 

 America, surpassing in extent, probably, those of any 

 other scientific traveller. A mere enumeration of these 

 journeys can alone be given here, in order to show how 

 much was accomplished amidst all the difficulties due to 

 climate, scarcity of food, scanty means, and imperfect 

 means of transportation, aggravated by solitude and 

 i ill-health. 



After a few months in Para and its vicinity, he moved 

 to Santarem, at the mouth of the Tapajoz River. Here 

 he remained for a year, collecting and studying the 

 remarkable shrubby vegetation which surrounds the 

 town, consisting largely of species then entirely new to 

 botanists. During this time he made an exploration up 

 the river Trombetas and its tributary the Aripecuru to 

 the limit of canoe navigation. The following year was 

 spent at Manaos (Barra do Rio Negro) exploring the 

 surrounding forests and streams. He next ascended the 

 Rio Negro in a large boat of his own, so as to be able to 

 collect and preserve plants during the voyage. Two. 

 months were occupied in ascending the river as far as San 

 Gabriel, situated on the cataracts of the Rio Negro, where 

 he rested seven months, making numerous canoe excur- 

 sions across the river to the various islands and to 

 tributary streams, not without danger amid the roaring 

 waters produced by the granite rocks and reefs which for 

 some miles here fill the broad river-bed. 



Spruce next ascended the Uaupes River as far as the 

 first cataract at Panure or San Jeronymo, which he made 

 his headquarters for another seven months. Here he 

 was delighted by the richness and novelty of the forest 

 vegetation, which was almost wholly new in species, and 

 even in some of the genera, .Many of the loftiest trees 

 had flowers of extreme beauty, especially those of the 

 natural orders VochysiaceJe, Tiliaccri?, Bombaceee, 

 Lecythideae, Rhizoboleae, and Rubiacea;, and to add to 

 the botanical interest of the district, when the rainy 

 season brought the flowering of the forest trees to a close, 

 the ground beneath them became ornamented with 

 thousands of curious herbaceous plants, mostly leafless 

 but adorned with delicate or brilliantly coloured flowers. 

 These belonged mainly to the genera \'oyria, Burman- 

 nia, Ptychomeria, and the TriuridccC. Here also fungi 

 were more abundant than in any other locality visited, 

 and about 200 species were collected, many of which were 

 as varied and brilliant in colouring as the flowers them- 

 selves. 



Leaving the Uaupes the traveller made his next head- 

 quarters at San Carlos, the first village in Venezuela 

 situated on the north bank of the Rio Negro, not far 

 from the entrance of the Cassiquiare. From this station 

 excursions were made up the Rio Negro and many of its 

 tributaries, and also through the entire length of the Cassi- 

 quiare to Esmeralda on the Upper Orinooko. He was 

 now in the country explored by Humboldt and Bonp- 

 land nearly a century before, and collected hosts of 

 plants, which were known only from the specimens sent 

 home by those botanists, together with considerable 

 numbers of new genera and species. In order to procure 

 food in this notoriously hungry region, he made a special 

 journey from San Carlos to the cattle district of the 

 cataracts of Maypures on the Orinooko, travelling over 

 the portage of Pimichin which forms a narrow water- 

 shed between the two great river systems. After twenty 

 months in this district he descended again to Manaos,. 

 from which he had been absent three years, and pre- 

 pared for his great journey to the Andes. 



Ascending the main stream of the Upper Amazon, and 

 entering its great southern tributary, the Huallaga, he 

 passed beyond its first rapids, and by means of a small 

 western affluent and a day's journey overland, reached 

 Tarapoto. This is a town of about 7000 inhabitants,. 



