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NOTES AND CORRESPONDENCE. 



Another Object Finder— As a subscriber to your Journal 

 from its commencement, and having never before troubled 

 you with a communication, I hope you will not refuse 

 admission to one upon a subject that' has repeatedly been 

 brought before your readers already, but which, in my 

 opinion, will still bear a little further consideration. 



I allude to the article of " Object Finder/' Almost every 

 microscopist must be too well aware of the difficulty of 

 quickly finding some particular scale, hair, desmid, diatom, 

 &c, &c, with a very high power, say a twelfth or sixteenth, 

 when the atom which we especially desire to examine is sur- 

 rounded by hundreds of others, which, as we slowly roll 

 them over the field by means of the traversing-plates, &c, 

 confuse and weary the eye, until the operator's patience is 

 completely exhausted. 



The difficulty, of course, is greatly enhanced when, as 

 is frequently the case, the embarrassed seeker is eager to 

 exhibit the minute particle to friends who are anxiously 

 awaiting his success. It is, therefore, no wonder that so 

 much ingenuity has been exerted to devise various means 

 to enable us to pounce at once upon the desired object, 

 without that almost interminable bungling that I have de- 

 scribed. But I believe they have all, more or less, been 

 found unsatisfactory; some depending on unsightly circles, 

 &c, scratched, or otherwise marked, on the object-slider 

 itself; others consisting of various kinds of plates, finely 

 graduated, the said graduations requiring to be found, 

 focussed, adjusted, &c, and the said plate, moreover, being 

 itself a separate piece of apparatus, to be looked for, and 

 adapted to the instrument, whenever its use may be required. 



Now, all this time, there has been in existence an appa- 

 ratus that forms (or should form) part of every complete 

 microscope; and which I verily believe to be the best 

 " finder" that can be used. 



I allude to the instrument called, in opticians' catalogues, 

 a " double nose-piece." 



In order to shorten the labour of finding an object with a 



