1874.] On the Motions of Nebulae towards or from the Earth. 251 



examined*. In these plants the section of the central bundle exhibits a 

 form of the letter H. The vessels of the large central transverse bar are all 

 reticulated ones : the greater part of those of the terminal vertical bars 

 are of the same character ; but the outermost vessels of those latter 

 structures are barred or quasi-scalariform. As in the case of R. duplex, 

 already described, these outermost layers of barred vessels, accompanied 

 by a few reticulated ones, become detached alternately from opposite sides 

 of the H-shaped central bundle. Passing quickly through a thin delicate 

 cellular inner bark, they enter the coarser parenchyma of a middle one, 

 as two irregular clusters of vessels with one common investment pro- 

 longed from the innermost bark. On reaching the outer bark they become 

 two distinct cylindrical bundles, each with its own delicate cortical 

 investing layer ; and thus invested, they emerge from the primary petiole 

 to supply the secondary rachis. 



The Oldham specimens of Racliiopteris bibractiensis agree with those 

 described by M. Renault in having all their vessels of the barred type. 

 The outer bark projects at numerous points in large conical abortive 

 hairs, which almost assume a spinous aspect. 



The author further figures and describes the section of a vascular axis, 

 with a central cellular medulla surrounded by five contiguous crescentic 

 masses of vascular tissue, whose concavities are directed outwards. This 

 plant appears identical with the Anarchopteris Decaisnii of Renault. 



II. " On the Motions of some of the Nebulae towards or from 

 the Earth/' By WILLIAM HUGGINS, D.C.L., LL.D., F.R.S. 

 Received January 26, 1874. 



The observations on the motions of some of the stars towards and 

 from the earth which I had the honour to present to the Royal Society 

 in 1872 appeared to show, from the position in the heavens of the 

 approaching and receding stars, as well as from the relative velocities of 

 their approach and recession, that the sun's motion in space could not be 

 regarded as the sole cause of these motions. " There can be little doubt 

 but that in the observed stellar movements we have to do with two other 

 independent motions namely, a movement common to certain groups 

 of stars, and also a motion peculiar to each star"t. 



It presented itself to me as a matter of some importance to en- 

 deavour to extend this inquiry to the nebulae, as it seemed possible 

 that some light might be thrown on the cosmical relations of the gaseous 

 nebulae to the stars and to our stellar system by observations of their 

 motions of recession and of approach. 



Since the date of the paper to which I have referred, I have availed 



* Annales des Sciences Naturelles, 5 e eerie, Bot. tome xii. 

 t Proceedings of the Royal Society, vol. xx, p. 392. 



