February 27, 1913] 



NATURE 



1 1 



the colour test for nitrites. It is thus clear that the 

 two processes of bleaching carrotene, namely either 

 by oxygen or by nitrogen peroxide, are quite distinct. 

 It is assumed that the same holds good in flour and 

 that artificially bleached flour, in which normally about 

 one-third of the colouring matter has been destroyed 

 by bleaching, and naturally aged flour are not quite 

 the same thing. 



It is shown by Dr. Monier-Williams that unbleached 

 flour, stored in small bags, as is customary in the 

 retail trade, gradually loses its colouring matter, and 

 at the same time picks up nitrites, which in time may 

 amount to i'4 parts of NaNOj per million. This is 

 much the same quantity as is present in the freshly 

 milled bleached flour typical of the London mills, - 

 which, although it loses further colouring matter on 

 storage, does not absorb any more nitrite. Actually 

 after two months' storage bleached and unbleached 

 flours are practically identical. Samples of very 

 heavily bleached flours had altered after two years' 

 keeping, so that they then only contained about as 

 much nitrite as ordinary unbleached flours kept for a 

 few months. 



The interesting conclusion is drawn that under 

 ordinary conditions of storage there is an approximate 

 figure towards which the nitrite content of all samples, 

 whether liighly bleached or unbleached, will eventually 

 converge. 



With the cooperation of Mr. Kirkland, Dr. Monler- 

 Williams has tested the baking qualities of some 

 heavily bleached flours. Mr. Kirkland reports that all 

 the loaves were of excellent quality, and had no re- 

 marl<able taste or smell. The one exception — flour 

 containing too times the usual quantity of nitrite — 

 gave a loaf which did not rise so well and possessed 

 a somewhat rancid, oily taste. 



Leaving any ethical considerations as to the pro- 

 prietv of bleaching flour entirely out of account, this 

 renort serves to establish conclusively that there is no 

 scientific evidence that bleaching by means of traces 

 of nitrites is injurious, and it is now proved that the 

 presence of traces of nitrites in stored flour is a natural 

 course of events. 



REEVES'S NIGHT MARCHING WATCH. 

 lyiESSRS. C. F. CASELLA AND CO., LTD., 

 "■'■^ have submitted a "night marching" watch," 

 designed by Mr. E. A. Reeves, and costing 2I. 155. 

 This is an ingenious device intended to help travellers 

 to know their bearings when moving at night, pro- 

 vided that they are able to recognise the brighter stars. 

 The stars made use of are Aldebaran, Rigel, Sirius, 

 Procyon, Regulus, Denebola, Spica, Arcturus, 

 Antares, Altair, Fomalhaut, Capella, and, of course, 

 by day the sun. The positions of these, together viJith 

 the da\'s of the months, are printed on a ring outside 

 the watch face, but under the watch glass, and 

 capable of being turned by the bezel (which unfor- 

 tunately is smooth instead of being milled) so as to 

 bring the date against the hour XII. Then the hour 

 on the watch face under any star's position when 

 multiplied by two is the time measured from noon 

 to this star's meridian passage. A rectangular mark 

 of luminous radium paint carried on the star rim is 

 then set to this doubled time, and the watch is ready 

 for use with that star. 



The hour hand carries a luminous projection which 

 rides over the edge of the star rim, and as this hand 

 rotates in the watch twice as fast as the earth rotates 

 or the star appears to go round, the angle between 



2 In other d..., 

 often adopted 



where a very white flour is reciuired a stronger bleach 



NO. 2261, VOL. 90] 



the two luminous marks already described as sub- 

 tended at the centre of the watch, is double the hour 

 angle of the star. But the angle at the centre is double 

 the angle subtended by the same arc at a point on the 

 circumference, and therefore these two marks will 

 subtend the star's hour angle at any point on the cir- 

 cumference on the other side of the watch. .\ 

 luminous arrow-head is therefore placed upon the 

 edge of the glass, which is capable of being turned 

 roimd without turning the bezel. When the arrow 

 mark is removed from the other two, and the watch 

 face is inclined roughly to the colatitude with the first- 

 named luminous mark at the upper side, and then 

 turned in azimuth until a line passing through the 

 arrow and tlie other maric is directed towards tlie 

 star, then tlie first luminous mark as seen from the 

 arrow will be in a southerly direction. 



As is usual with astronomical things, there are 

 certain cases where the rules have to be turned inside 

 out (as, for instance, when a star crosses the meridian 

 to the north), and these are explained in the pamphlet. 

 Unfortunately this pamphlet is ambiguously worded, 

 and anyone not understanding the principle would 

 have great difficulty in finding out what to do. The 

 question which must occur to anyone at all familiar 

 with the night sky is this : Has not ingenuity been 

 misplaced ? Even if the pole star be not visible, there 

 is very little doubt, at least in the northern hemi- 

 sphere, where it is. In the southern hemisphere, it 

 is true, there is a great blanlc in the polar region, but 

 it does not take long to learn the relations of the 

 conspicuous southern stars to the pole. While there- 

 fore some people might lilie to use the watch and 

 enjoy the use of it on account of its ingenuity, others 

 might prefer in practice to do without. 



THE VEGETATION OF THE TRANSCASPIAN 

 LOWLANDS. 



T^R. O. PAULSEN has published an English 

 -'-' edition, revised and corrected by Dr. W. G. 

 Smith, of Edinburgh, of his important memoir on 

 "The Vegetation of the Transcaspian Lowlands." 

 This memoir forms the first part of the biological 

 section of the botanical results of the second Danish 

 Pamir expedition — the systematic part of the botanical 

 results having been already published as the examina- 

 tion of the various natural orders was completed — and 

 contains 279 pages, with 79 illustrations, and a map 

 of the area studied. After describing the situation 

 and boundary of the region examined, together with 

 the general geological and climatic characters of 

 Transcaspia, the author deals in considerable detail 

 with the vegetation, which he classifies under the 

 headings of five distinct plant-formations. These 

 formations are the riverside thickets (bushland) and 

 four tyoes of desert formation (salt, clay, sand, and 

 stone deserts). 



The second half of the memoir is devoted to an 

 extremelv interesting account of the various biological 

 types of growth forms. The author follows Raun- 

 kiaer's svstem according to which the plants are 

 arranged in classes depending upon the way in which 

 they live through unfavourable seasons, special em- 

 phasis being laid on the degree and kind of protection 

 afforded to the dormant shoot-tips. Of the 768 species 

 listed, ncarlv half are annuals which live through the 

 hot, drv summer as seeds, having flowered during the 

 rainv period; trees and shrubs are few and small, 

 chieflv tamarisks, Callicfonum (Polygonacpae\ and 

 shrubby Papilionaccr; (pspeciallv Astraealus') ; the 

 Compositae of the Transcaspian flora include 103 



