May 23, 1889] 



NATURE 



83 



thus producing a steady powerful flame of beautiful 



appearance. This porcelain tube forms the lower portion 

 of the chimney, around which is placed the regenerator. 

 The products of combustion, in passing away, heat the 

 regenerator by conduction, through the metal of the 

 same ; and the air, passing upwards and downwards 

 between its metallic surfaces, as also indicated by arrows 

 in the diagram, carries the heat back to the llame. The 

 lamp is closed below by a glass globe, which, however, 

 need not be removed for lighting, as a flash-light is 

 provided for that purpose. 



These lamps are made of different sizes, with a con- 

 sumption varying from 10 to 40 cubic feet of gas per 



hour ; with London gas they give a light of from ten to 

 twelve candles per cubic foot consumed per hour, which 

 is from four to five times as much as is obtained with 

 ordinary burners. It would have been easy to arrange 

 the lamp we have just described so as to produce a much 

 higher result than that given above ; but, to produce this 

 effect, the air supplying the burner would have to be 

 passed through small channels, which would be liable to 

 be partly closed up by oxidation, and thus, by reducing 

 the air-supply, cause the lamp to smoke, whereas the 

 Siemens lamp has been specially designed to provide 

 against this unpleasantness, to which regenerative gas- 

 lamps are more or less liable. 



H EI N RICH GUSTAV REICHENBACH. 



(~\^ the 6th inst., there died at Hamburg, in the sixty- 

 ^-^ seventh year of his age, a botanist long and fami- 

 liarly known to his English colleagues, and one whose 

 name will be preserved in the annals of botany. 



Heinrich Gustav Reichenbach had been Professor 



of Botany and Director of the Botanic .Garden at Ham- 

 burg since 1862. He was born in Leipzig, his father 

 having been also a well-known botanist and Professor in 

 Dresden from 1820 till his death in 1879. Much of the 

 younger Reichenbach's work was done in association with 

 his father, with whom he co-operated in the production of 

 the later volumes of the carefully elaborated hones Flora 

 Gerinanica ct HclveHccc. But work of this character, 

 carefully and critically executed though it was, was cast 

 into the shade by the magnitude of his labours among the 

 Orchidacea.\ Reichenbach the younger devoted more 

 than forty years of his life, almost (though, as we have 

 seen, not quite) exclusively to the study of orchids. 



At the commencement of his career, Lindley was still 

 in the plenitude of his powers, but when, some quarter of 

 a century since, the great English botanist failed in health, 

 and subsequently died, there was no one to question the 

 supremacy of Reichenbach so far as orchids were con- 

 cerned. 



From that time to the present the Hamburg Professor 

 has reigned with undisputed sway. His reign corresponds 

 in its progress with the development of that passion for 

 the cultivation of orchids which has attained such large 

 proportions in this country. This is a fashion which at 

 present shows no sign of waning here, whilst it is spreading 

 widely in other countries. It has proved of signal service to 

 orchidology in its systematic aspect, and to a less degree 

 to morphology and biology, as witnesses, to cite only one 

 illustration, the work of Darwin on the " Fertilization of 

 Orchids." A hundred years ago about three hundred 

 species were catalogued in the later editions of Linnasus's 

 " Species Plantarum," and those three hundred were very 

 imperfectly known or illustrated. About sixty years have 

 elapsed since Lindley began his first systematic enumera- 

 tion of the genera and species, a work in which he was 

 at first greatly aided by the previous labours of Brown 

 and by the splendid drawings of Bauer. In 1840, at 

 the conclusion of the "Genera and Species," Lindley men- 

 tions that the total number of species included iVi that 

 work amounted to 1980, of which the author himself had 

 analyzed three-fourths. Later estimates in the " Vegetable 

 Kingdom " bring the numbers up to 394 genera and 3000 

 species. Bentham, in 1883, calculated the known species 

 as between 4500 and 5000 ; while Pfitzer, the most recent 

 census-maker, gives the extreme number of species as 

 10,000. Granting that this latter figure is excessive, it at 

 least suffices to illustrate the enormous increase in our 

 knowledge of orchids. This advance has been, as we 

 have said, chiefly due to the orchidomania which origi- 

 nated as a consequence of the exhibition of a few remark- 

 able forms at the early meetings of the Horticultural 

 Society, and which has been growing ever since. We 

 never heard of any material good arising from the tulipo- 

 mania ; but the passion for orchids, involving, as it has 

 done, the exploration of the countries where they grow, 

 and the collection and transmission of countless thou- 

 sands of specimens, live and dead, not only of orchids 

 but of plants of other orders also, has most undoubt- 

 edly been of great service to botany, and it has served 

 also to illustrate the great, but often unappreciated, 

 value of gardens as instruments of scientific research. 

 Dried specimens of orchids afford a sorry spectacle at 

 best, and the characters upon which the distinction of 

 genera and species depend are readily obliterated or lost 

 in the drying process. But in gardens the material is 

 often ample, and in the best condition for examination. 



Reichenbach, as we have seen, was able to avail himself 

 to a much larger extent than any of his predecessors of 

 the facilities offered by gardens. He became the acknow- 

 ledged referee on all questions of nomenclature, and to 

 him were constantly submitted fresh specimens for ex- 

 amination. Of late years, also, hybridization has been 

 practised to a large extent among orchids, and the resul- 

 tant hybrids found their way to Hamburg, there to be 



