88 



method of making type slides, in stating that, when numbering 

 the backgrounds for reduction by photography, " Note must also 

 be taken to write the figures ' reversedly,' for the microscope 

 reverses the images." If the figures are normally written on the 

 prepared card the negative reverses and the print puts matters 

 right again. But the ordinary compound microscope not only 

 reverses from right to left — it inverts also ; and so, if the figures 

 are correct on the print, they are equally correct when viewed 

 with the microscope, the slip being, of course, placed so to allow 

 for the inversion. 



On the whole, we can warmly recommend this little work to 

 the notice of those who are at all interested, or have any desire to 

 be interested, in the subjects with which it deals. F. P. S. 



The Metric and English Weights and Measures. By P. E. 

 Badley. 4| x 3j. 64 pages. London, 1907. Published 

 by the Author, 30, Theobald's Eoad, W.C. Price One 

 Penny. 



The extensive adoption of the Metric System in optics and 

 chemistry, largely due, no doubt, to the great strides which have 

 been made of late in these and kindred sciences by Continental 

 investigators, has made it a matter of necessity for the serious 

 worker to more or less acquaint himself with the decimal method 

 of calculation. We note, therefore, with pleasure, the appearance 

 of this unpretentious but extremely useful little book, which 

 cannot fail to find favour in the role of a time-saver with every one 

 engaged upon work where the necessity arises for the conversion 

 of the Continental weights and measures into those generally 

 employed in this country, and vice versa. For the practical man, 

 facilitated methods for rapid approximate comparisons are given ; 

 but the requirements of the most exacting are catered for, 

 inasmuch as the important standards are compared to the extent 

 of sixteen or more places of decimals. We hope that this little 

 work will meet with the success it deserves. F. P. S. 



Elementary Microscopy. By a clerical error the price of this 

 work, reviewed in the last number of the Journal, was stated to 

 be 2s., whereas it should have been 3s. F. P. S. 



Journ. Quekett Microscopical Club, Ser. 2, Vol. X., No. 60, April 1907. 



