126 



NATURE 



[September 15, 19 10 



and zinc paints wliicli are a big feature of tlie American 

 paint industry, and are obtained by subliming mixed 

 lead and zinc ores, and wliich contain various propor- 

 tions of zinc oxide and lead sulpfiale, are fully 

 described. The preparation also of the oxides of 

 lead and lead chromes is dealt with, and the prepara- 

 tion and properties of zinc sulphide paints. 



A ver)' complete account is also given of the elabor- 

 ate practical tests of various paints which are being 

 made on special experimental stations in the United 

 States at present, with the view of deciding which 

 paints are most durable for outside use. These experi- 

 ments are giving some very valuable results. For 

 instance, the usual assumption in this country that 

 white lead is the best pigment for protection of outside 

 surfaces has apparently been quite disproved by these 

 results. Zinc white, or mixtures of zinc white with 

 white lead, prove to be more durable. These e.xperi- 

 ments are still being continued and the results pub- 

 lished from time to time, and should be carefully 

 watched by architects and engineers in this country, 

 where similar experiments might well be carried out. 

 The physical and chemical properties of these various 

 whites and their analyses are also thoroughly dealt 

 with ; in fact, the whole book contains a great deal of 

 very valuable information written from the American 

 point of view, and should therefore be of special 

 interest to all those connected with the paint industry 

 in this country. A. P. Laurie. 



METEOROLOGICAL TABLES. 



Tables for the Reduction of Meteorological Observa- 

 tions. Prepared by Dr. G. C. Simpson, under 

 the direction of Dr. Gilbert T. Walker, F.R.S. 

 Pp. ix + 95. (Calcutta: Government Printing Office, 

 1910.) 



THE present revised edition of Blanford's meteor- 

 ological tables, prepared for the routine work ot 

 the Indian meteorological service, contains in all six- 

 teen tables, of which the first and last pairs are for the 

 interconversion of barometric heights and of tempera- 

 tures in the English and metric systems. The remain- 

 ing tables are in English units. The relationship 

 I metre = 3937079 inches, adopted from the interna- 

 tional tables, is an example of fictitious accuracy 

 which might be discarded in view of the values found 

 by Rogers (1893), 39\i7oi55, and Benoit (1902), 

 39'370ii3. The same criticism applies to the ex- 

 pressions for the corrections to tlie barometric height 

 H, for the variation of gravity with latitude (A), and 

 altitude (/;), viz. 000259 cos 2A H and 5"97 x lo-'/i /i. 

 The arrangement in table vii., for reducing the baro- 

 meter to sea-level, or for finding differences of height, 

 is excellent. The logarithms are tabulated, and the 

 temperature and humidity terms have been combined 

 by assuming a constant value for the mean air-pres- 

 sure occurring in the latter ; the result is that the 

 complicated process involved in applying the Smith- 

 sonian or international tables has vanished, and the 

 desired value may be obtained by a simple calculation 

 as accur.-Uely as the observations ordinarily allow. It 

 NO. 2133, VOL. 84] 



is, however, not necessary to apply the latitude correc- 

 tion to the barometer readings in finding differences 

 of height. 



The major part of the volume i>. devoted lo humidity 

 tables for reducing psychrometric observations for 

 temperatures between —20° and 130° F., and for pres- 

 sures 297, 277, 25'8, 23'4, i9'7 inches. Presumably 

 258, 23"4 were retained because they are approximately 

 the mean pressures at altitudes of 4000 and 7000 

 feet respectively, but it seems inappropriate to deter- 

 mine the increments of the argument, pressure, by 

 unequal increments of altitude. The tables are strictly 

 applicable to observations taken in light winds only. 



A useful little table gives the mean daily range of 

 pressure determined from ten tropical stations. 



The tables are well and carefully printed on good 

 paper, but the volume might with advantage be made 

 of a more convenient size. The adoption of the prin- 

 ciple, common in logarithmic tables, of neither print- 

 ing nor allowing space for unnecessary figures, would 

 prrmit this without sacrificing clearness. 



E. Gold. 



PLANTS AND GARDENS. 

 Sweet Peas. By H. J. Wright. Pp. xi+uG. Price 



is. 6d. 

 Paiisies, I'iolas, and ]'iolcis. Isy Wai. Cuthbertson, 



J. P., and R. Hooper I'earson. Pp. xi + ii6. Present- 



Day Gardening, edited by R. Hooper Pearson. 



(London and Edinburgh : T. C. and E. C. Jack, 



n.d.) Price is. 6d. 

 Die Hicde. By W. Wagner. Pp. 200. (Leipzig: 



Quelle and Meyer, n.d.) Price i.So marks. 

 Niedere Pflanzen. By Dr. R. Timm. Pp. 194. 

 (Naturwissenschaftliche Bibliothek fiir Jugend und 



Volk.) (Leipzig : Quelle and Meyer, n.d.) Price 



1.80 marks. 

 Das Holz. By H. Kottmeier and F. Lhhnann. Pp. 



iv-l-143. (Leipzig: Quelle and Meyer, 1910.) Price 



1.25 marks. 

 Der Pfianzengarten, seine Anlage und seine ]'erwer 



kung. By Prof. F. Pfuhl. Pp. 152. (Leipzig: 



Quelle and Meyer, 1910.) Price 2.50 marks. 



THE dictum as to the endless making of books 

 may be applied with particular force to works 

 relating to gardening and nature study at the present 

 day. To such an extent has the gardening fashion 

 seized the country that every class of plants must now 

 have its own special treatise. The two books first on 

 the list are the opening volume/ of a series entitled 

 " Present-day Gardening," produced under tlie editor- 

 ship of the editor of the Gardener's Chronicle, and 

 they appear to be excellent alike in their coloured 

 illustrations and in the letterpress. The illustrations 

 are remarkably good examples of colour printing, and 

 it is only in the case of some of the lilac shades that 

 some criticism might be made. The text is both in- 

 teresting and practically useful, and the plan followed 

 is similar in both volumes, opening with some his- 

 torical notes, general culture, the value of the plants 

 for decoration, an account of standard varieties, &c. 

 If forthcoming volumes maintain the level of those 



