122 



KNOWLEDGE. 



[June 1, 1896. 



The Bontgen rays are probably of various wave-lengths, 

 and are not analogous to light of one definite colour. The 

 absence of any phenomena of dilYraction does not, therefore, 

 prove that they are not ultra-violet vibrations. Before 

 diffraction experiments can bo successfully performed a 

 means must be found for sifting the Rontgen rays, and 

 separating out the components dilTering in wave-length. 



The evidence that irregular rellection of Ivontgcn rays 

 occurs is accumulating, and, so far as can be judged at 

 present from the results of the numerous experiments 

 already carried out, it seems probable that this newly 

 discovered form of radiation will turn out to bo a form of 

 transverse vibration in the ether of much smaller wave- 

 length and more rapid than that which produces ordinary 

 light. 



It must be remembered that the visible vibrations 

 constituting light have a range, from the dark red, or 

 slowest, to the violet, or most rapid, of about an octave. 

 Vibrations which are a little more than twice as rapid as 

 those of red light do not affect our eyes. There is no 

 reason to suppose that disturbances or changes m the 

 ether many times as quick ..s those of red light do not 

 exist. Some of these ultra violet vibrations have already 

 been investigated and have become known, and it may 

 well be that some still more swift and hitherto unsuspected 

 vibrations have been manifesting their existence to us by 

 the effects first noticed by Lenard and Riintgen, and since 

 so diligently investigated by the numerous observers who 

 have followed them. 



BRIEF DESCRIPTION OF THE ORCHID 

 PHOTOGRAPHS. 



By H. A. Bi RiiERKY, F.R.H.S. 



THE accompanying illustrations are from photographs 

 of a few specimens from the Right Hon. J. 

 Chamberlain's collection of orchids. 

 Fig. 1 represents a specimen of Cattleya wossice, 

 variety M'ai/niri, a very rare and most beautiful 

 orchid. It is a native of Venezuela, and thrives best when 

 grown in an intermediate temperatm'e. The species as a 

 whole is a richly and most varied coloured one. The 

 variety ^Vaijiwri is the pure white form. The section to 

 which this plant and Cattlfi/a weiulelii (to be described 

 later on) belong is the "labiate" section, so named on 

 account of the very large and beautiful lip, or labellum, 

 which is a characteristic of the plants. All species belonging 

 to this order have their pure white varieties, which are in 

 all instances very rare and costly. 



Fio'. 2 is a specimen of Ci/pripcilium helldtulum, a species 

 coming from Cochin China. The flower is very striking, 

 the ground colour being white and the whole densely 

 spotted with brownish purple. The plant succeeds best in 

 an intermediate temperature, and should be grown in a 

 compost of strong loam mixed with limestone. 



The genus Ci/pripeiliuiu, to which belong the so-oalled 

 " lady's slipper orchids," is a very large and popular one, 

 inhabiting both Asia and America. Those from the North 

 of America are quite hardy. There is, moreover, one 

 {€. caleolus) that is a well-known European species, and 

 was once a wild plant in England, but has now become 

 exterminated. 



Fig. 3 is a very beautiful orchid coming from Burmah, 

 and called ]>< mlrubium foniio.suin t/iiiiintt'iiiii. The genus to 

 which it belongs is a very large one, and species belonging 

 to it are found scattered nearly over the whole of the con- 

 tinents of Asia and Australia. They are for the most part 



very warm-growing orchids, and the species here depicted 

 always requires the warmest department and grows best 

 planted in small pans suspended from the roof. It llowers 

 during August and September. Tlie flowers are pure white, 

 with the exception of an orange blotch on the labellum, 

 and are borne at the apex of the newly-formed pseudo-bulbs. 

 Ciittlri/d niiiuirHi, a Specimen of which is shown in 

 Fig. 4, belongs to the same very popular genus as the 

 subject of Fig. 1. The genus was founded in honour of 



Fig. 5. — MiUoiiia vcxrllaria. 



William Cattleya, of Barnet, Herts, who was a great 

 lover of orchids in his day. C nimdflii is a very attrac- 

 tive and showy orchid, and is one of the most lovely 

 of them all. The flowers are of great beauty and most 

 delicately tinted, from light pink to a deep rose colour. Its 

 native habitat is 

 New Granada. 

 The temperature 

 most suited to its 

 requirements is an 

 intermediate one. 

 It flowers in April 

 and May, and 

 grows best when 

 planted in peat 

 and sphagnum 

 moss. 



The genus 

 Miltoniu (named 

 after Viscount 

 Milton, afterwards 

 Earl Fitzwilliam) 

 is one containing 

 several very beau- 

 tiful orchids, some 

 preferring the 

 temperature of the 

 warmest house, 

 and others the in- 

 termediate house 

 temperature. 

 M. vexillaria 

 — Fig. 5 — from 

 New Granada, is 

 one of the latter 



Fii>. 0. 



Oncidiutn papilio. 



It is sometimes known as the " standard-bearer orchid." 

 It is one of the most showy and beautiful of the genus, 



