MEMORANDA. 219 



before them ; and are^ at the same time, of far more practical 

 utility.— Q. E. D. 



Hypersthene. — A correspondent has written me that though 

 he has examined this object together with one of our first 

 London opticians, yet " we could not make it that wonderful 

 object you speak of." Very probably not; for among the 

 different specimens I have examined, I have not seen another 

 equal to mine ; and this leads me to remark that I wish our 

 object-preparers would turn their attention more to it ; for, 

 being of a crystalline texture, a good deal may depend on the 

 angle at which it is cut. When it is first-rate, and exhibited 

 as described (April number, p. 135), with inch objective and 

 Lieberkiihn {side reflexion will not do), and at night by intense 

 lamp-light, without a " modifier," I think it stands quite at 

 the head of what may be called " the gorgeous class " of 

 objects ; and I find it more frequently elicits that rapturous 

 OH ! ! ! (which sounds so delightfully at a microscopic 

 soiree) than any other of that class ; e.g. peacock copper, 

 ruby copper, needle antimony, iron ore from Elba, elytron of 

 Curculio regalis, &c. Before quitting this subject allow me 

 to correct a slight error. Your proof-reader, by altering my 

 stop, has altered my meaning. I wrote, " I seem to see part 

 behind part," &c. ; just as in looking at the sky we see cloud 

 behind cloud ; or, in a forest, tree behind tree, fee. This is the 

 case more especially when we use the binocular microscope. 

 The mention of " microscopic soiree " leads me to write a few 

 words on the subject of the 



Microscopic turn-tables, which are such an admirable aux- 

 iliary at those friendly meetings. Very handsome ones are 

 made of iron, walnut, &c., expressly for the purpose ; but, as 

 many may not choose to incur the cost of them, it is well to 

 mention (what may possibly not occur to every one who 

 possesses the article) that one of the ordinary revolving 

 tables, with drawers and knobs (without which a gentle- 

 man's library is not considered complete), answers the pur- 

 pose to admiration. 



The usual size admits eight sitters comfortably, and the 

 perfection of the "round game at microscope," as I call 

 it, would of course be to have as many instruments as there 

 are players. 



But as this would be too costly a game for many pockets 

 (unless, as in a " pic-nic/' each was to bring his own quota), 

 I find it best to place the instruments (whatever number there 



