170 Noll's ami i^uiniiculs. 



sheet to is. 6d. (when may we hope to see the price reduced to 

 the popular and convenient 'bob'?) but geologists have the 

 assurance that when once the final proofs have been revised no 

 colourists' errors or omissions will insidiously vitiate the work. 

 We have known rather important generalisations to be made on 

 the basis of a supposed unconformable overlap when the actual 

 junction was a faulted one, but the colourist had omitted the 

 necessary streak of Chinese white. Colour printing, it is to be 

 hoped, will secure uniformity of shade in contiguous maps, and 

 in this respect great improvements have been effected since the 

 production of the Geological Index Map (four miles to the inch), 

 in which the contrasts between what should have been identical 

 tints on adjacent sheets gave the mounted map somewhat the 

 aspect of a chequer-board. While we are speaking of the Index, 

 we ma}^ venture to utter a gentle protest against the short- 

 sightedness — not, we believe, at Jermyn Street -which permitted 

 the first edition of the Index Map to run out of print before a 

 new edition was ready to replace it ; the consequence is that 

 students and others desiring a copy of this most useful and 

 admirable map have been waiting weeks or months, and may 

 have an equal time still to wait before the maps are on sale. 



Is there no chance of our finding some knight-errant M.P. 

 who will undertake the righting of all the wrongs we have 

 suffered at the hands of the Ordnance Survey or the Treasury — 

 we cannot apportion the blame — ^in the matter of good, cheap 

 and easily purchasable maps. Much has been done, but more 

 remains to do, and many geologists, to say nothing of engineers, 

 sanitarians, and land owners, lament the falling off in the 

 quality of the work put into our six-inch maps since photo- 

 zincography took the place of the old methods of producing 

 plates. 



LEPIDOPTERA ILLUSTRATING MKLAXISM. 

 At the meeting of the British Association to be held this year at 

 York (August 1-8), it is proposed that there shall be an exhibition 

 of British Lepidoptera illustrating Melanism. The Organising 

 Committee of the Zoological Section invite those who are willing 

 to take part to communicate with Mr. L. Doncaster, Zoological 

 Laboratory, Cambridge, stating the species and number of 

 specimens which they are prepared to send. It is ixpected that 

 a paper on ' Melanism ' will be read at the meeting by Mr. G. T. 

 Porritt, of Hudderfield, and that it will be followed by a 

 discussion. 



N'.itiir.ilis(. 



