December 22, 1923] 



NA TURE 



89: 



On the vexed question of the proper formula to 



apply for the determination of the present value of a 



deferred annuity in which two rates of interest are 



involved, Prof. Louis recommends (p. loi) that which 



|was, we beUeve, first put forward by Mr. George King, 



id is accepted by the Inland Revenue in valuations 



)r the purposes of probate. The simplest form in 



i^hich this can be stated is that given by the reviewer 



a work of which he is joint-author, namely, where : 



Y.P. = years' purchase. 



a! = the amount to which iZ. per annum ac- 

 cumulates in e years at r per cent. 

 A = the amount to which \l. per annum ac- 

 cumulates in t years at r per cent. 

 r = the accumulative low rate of interest. 

 R = the remunerative high rate of interest. 

 <^ = the period of deference. 

 g = the period of enjoyment. 

 t — the total period = </ + g. 

 a 



ar' 



1 + 



len 



Y.P.= 



Allusion has been made at the commencement of 

 lis review to want of adherence to fundamental 

 jrinciples in valuation of mines for purpose of assess- 

 ment of rates, the basis of which is, by law, the annual 

 value. There are no less than sixteen different methods 

 of assessment in use in England and Wales, but there 

 can be no doubt that the fairest is that advocated by Sir 

 E. Boyle, namely, to value the surface works and plant 

 as the non-directly productive works of a railway are 

 valued, and the mine on the gross receipts upon coal 

 raised, excluding colliery consumption, and deducting 

 therefrom the expenses incurred in getting and raising 

 the coal, i.e. to take as the value the net income 

 derivable from the coal. 



All who seek enlightenment on this and other 

 branches of the subject of valuation of minerals can- 

 not do better than study Prof. Louis's admirable and 

 comprehensive work. Richard Redmayne. 



Dutch Potters and their Work. 



Old Dutch Pottery and Tiles. By Elisabeth Neurden- 

 burg. Translated with .iVnnotations by Bernard 

 Rackham. Pp. xv + 155 + 59 plates. (London: 

 Benn Bros. Ltd., 1923.) 84^. net. 



IT is a pleasure to welcome this competent, scholarly, 

 and interesting account of that renowned pottery- 

 work of the Dutch craftsmen and artists which exer- 

 cised such a profound and quickening influence on the 

 potter's art as it was practised in all the countries of 

 northern and central Europe, especially during the 

 course of the eighteenth century. We already possess, 

 NO. 2825, VOL. 1 12] 



in English, quite a number of small handbooks which 

 treat of this important subject ; but here, at last, a 

 volume is presented which may be acclaimed as 

 worthy and complete in its text, and is also so hand- 

 somely illustrated as to satisfy every requirement of 

 the collector. 



One praiseworthy feature, which immediately arrests 

 attention, is the frank simplicity with which the many 

 troublesome questions concerning the date or even the 

 period of the various types of pottery and tile-work 

 manufactured in the different towns and provinces of 

 Holland are discussed and their origins elucidated. 

 The factories at Delft, most famous of Dutch pottery- 

 towns, are described at length, and we have interesting 

 personal accounts of their proprietors and the principal 

 painters in their employ ; though we are still, fortun- 

 ately, in the time when the proprietor of a pottery was 

 his own principal artist or master-craftsman. The 

 factories at Rotterdam, Haarlem, The Hague, and those 

 in the province of Friesland are not overlooked, though, 

 as is only to be expected, they do not receive the same 

 detailed notice, for their pottery was not of the same 

 importance either in quantity or in technical excellence. 



The descriptive account of the native peasant- 

 pottery and tiles, enriched with decorations in " slip " 

 or with more ambitious designs in " sgraffiato," strikes • 

 one as somewhat meagre and unilluminating. This is 

 a matter for regret, when we remember the extensive 

 and splendidly decorative use which was made of these 

 simple methods by our English potters of the seven- 

 teenth and eighteenth centuries. 



Of the famous tin-enamelled wares, with their 

 brilliant and effective painted decoration in blue or in 

 polychrome, the book gives an excellent and convinc- 

 ing account. We are shown, by a documented narra- 

 tive, how the processes were first introduced into 

 Holland and how the mingled stream of Italian and 

 Spanish influence fertilised the native art of the Dutch 

 potters ; either as a result of the incursions of Italian 

 and Spanish pot-painters or from the return of Dutch 

 potters who had travelled abroad for the increase of 

 knowledge. Thus, an account is given of one, Hendrik 

 Vroom, who travelled to the south of Europe to become 

 qualified as a painter in oils but repeatedly earned his 

 living while pursuing his studies by serving as a painter 

 of pottery ; working in Seville for an Italian potter and, 

 later on, at a majolica factory in Venice. By such 

 interchanges the art and craftsmanship were both im- 

 proved, for the Dutchman sharpened himself on the 

 more fiery metal of the South ; so that, when he turned 

 in earnest to the reproduction of Oriental designs, 

 borrowed from the fashionable porcelain of the Far 

 East, he was so well equipped that he was able to take 

 full advantage of the lessons taught by the greatest of 



2 B I 



