December 26, 1895] 



NATURE 



17 



<is against 850 in Mauritius. The larger number may 

 be accounted for by the greater elevation of Bourbon, as 

 well as the divergencies in the numerical representation 

 of the predominating natural orders. Some fourteen 

 fewer natural orders are represented in Bourbon, but, 

 in return, several orders are much more numerously 

 represented. 



It was known that Bourbon, as well as Mauritius, was 

 exceedingly rich in ferns and orchids ; yet few botanists 

 will be prepared for the fact that orchids outnumber the 

 two next highest orders combined. Orchids are absent 

 or very rare in small remote islands, and comparatively 

 rare in larger ones where there is a humid climate and 

 rich vegetation ; or even absent, Juan Fernandez, for 

 example ; and British India is the only large continental 

 area, so far as I am aware, in which orchids predominate 

 over any other order. Nearly 20 per cent, of the flower- 

 ing plants of Bourbon are orchids ; the total number 

 described being 172 species, and the author expresses a 

 doubt whether this is exhaustive. Three new genera 

 are proposed, one, I/emipcris, comprising twenty-one 

 species. Altogether seventy-two are described as new, 

 and they are about half epiphytic and half terrestrial. 

 Very few of these orchids are represented in the herbaria 

 of this country, and, indeed, many of the other endemic 

 plants of the island, especially the inconspicuous ones. 



Dr. Cordemoy describes three or four new genera 

 belonging to other orders, but mostly from somewhat 

 imperfect materials. The most interesting is a labiate 

 {Mahya stellata), supposed to be the only really in- 

 digenous member of the order, and exceedingly rare, 

 being found only on the summit of the Grand Benard, 

 at about 8500 feet. W. Botting Hemsley. 



TECHNICAL EDUCATION, 

 The New Technical Educator. Vols v. and vi. (London, 

 Paris, and Melbourne : Cassell and Co., Limited, 1895). 



THESE are the concluding volumes of a valuable 

 series of treatises on various technical subjects ; 

 the previous ones have already been noted in our columns. 

 All the subjects are dealt with in an admirable manner, 

 the author in each case being a specialist. The arrange- 

 ment of the work is such that in most cases each 

 volume contains information bearing upon a particular 

 subject. A good index has been placed at the end of the 

 last volume, and this very materially adds to the value of 

 the work. 



Prof W. H. Greenwood's treatment of the manufacture 

 of "Steel and Iron" is excellent. Commencing with the 

 ores, he takes the reader through all the many processes 

 in vogue, with ample illustrations and descriptions. The 

 question of tests, however, appears to be generally over- 

 looked. This is unfortunate, because it is of great 

 importance both to the manufacturer and the engineer. 

 In all modem specifications the quality of the material 

 to be used is always stated, either in the form of 

 mechanical or chemical tests. 



Another well-written section is that on " the Steam 

 Engine," by Archibald Sharp. In this case, also, the sub- 

 ject has been thoroughly dealt with from the beginning. 

 NO. 1365. VOL. 53] 



The illustrations and descriptions are of recent engines, 

 and boilers. Of the latter, the water-tube type has not 

 been overlooked ; more might have been said, however, 

 on the subject. The locomotive is represented by one 

 of Mr. Worsdell's compounds, and we are told that 

 "compound locomotives are being largely used." This 

 statement is scarcely correct, because in this country, at 

 any rate, they are at a discount. The same author has 

 much to say on the subject of "Gas and Oil Engines." 

 He omits to describe the porcelain ignition tubes now 

 largely used in place of iron. 



On " Engineering Workshop Practice," by severa 

 authors, we find much general information dealing with 

 the engineering trades. Taken as a whole, the treat- 

 ment flavours more of the amateur than of the trades- 

 man. The same cannot be said of " Electrical Engineer- 

 ing," by Edward A. O'Keeffe, because this subject 

 occupies a prominent position in these volumes, having 

 been particularly well written throughout. The last two 

 volumes treat more particularly of the construction of 

 incandescent lamps, accumulators and measuring instru- 

 ments, concluding with descriptions of the microphone, 

 telephone and phonograph, besides sundry details. 



"Civil Engineering" has also been creditably treated 

 from all points of view, the construction of roads naturally 

 coming much to the front, and the praises of Telford and 

 Macadam duly sung. An interesting account is included 

 on the rise and progress of railways ; when discussing 

 probable speeds, we read : " The desire is now for higher 

 speeds, and as much as 250 miles per hour is projected." 

 This statement is far-fetched, and should have been 

 omitted. The table giving train resistances, on p. 175, 

 vol. v., would have been of more value had the authority 

 been quoted. Further on, permanent way is discussed, and 

 we are informed that " sleepers are never placed under 

 the fish-joints." This statement is not correct. Another 

 inaccuracy is found on page 297, where we read " that 

 the driving-wheels of some locomotives have as much as 

 twenty-five tons on them " ; even the Great Northern 

 people would probably plead " not guilty " to twenty 

 tons on the driving-wheels of their famous single engines. 

 Much useful information has been brought together under 

 the heads of hydraulics, pumping machinery, lighthouses, 

 ships, &c. 



The " Dyeing of Textile Fabrics " is fully discussed, 

 the author being Prof. J. J. Hummel, of the York- 

 shire College ; treated very much from a chemical 

 point of view, dyers will find much to learn on this 

 subject. In answer to the question, " What is technical 

 education ? " we find some sound remarks from the pen 

 of Mr. Henry Cunynghame. He observes th^t the use 

 of a knowledge of principles, as compared with the mere 

 routine of the workshop, cannot be overrated ; this is 

 the distinguishing feature of the true mechanic from the 

 factory hand. Much has been done of late years to 

 encourage the formation of technical schools ; but more 

 must be done if we are to retain our present position as 

 a manufacturing country. A knowledge of principles, 

 both mechanical and chemical, is all-important ; and 

 these, in conjunction with machinery of the latest design, 

 must surely tell in the race for trade. 



The volumes before us will be of much use to those 



