NOTES AND CORRESPONDENCE. 
The Stanhoscope.—Until within the last few weeks I have 
been unable to obtain a lens sufficiently powerful to be 
useful and sufficiently portable to be convenient, in examin- 
ing diatoms on the spots where they were gathered. I 
have tried compound microscopes, and found their arrange- 
ments on the open field or on the seashore tedious and 
awkward. I have used the ordinary Stanhope and triplet 
lenses, but none of them gave satisfaction; the latter being 
much too low in magnifying power to enable me to deter- 
mine with any certainty what species or even genera I had 
gathered. 
The Stanhoscope, however, is excellently adapted for field 
purposes, its power, is great, ranging from 100 to 150 
diameters, its field is clear, and the method of using it is 
simplicity itself, all that is required being to place the object 
to be examined, say diatomace, desmidez, scales from moths’ 
wings, &c., on the square end of the lens, and then look 
through the apparatus towards the light. The size of the 
entire apparatus is only one inch in length and five eighths of 
an inch in diameter ; it is therefore exceedingly portable, and 
is also very cheap. The lens is of French manufacture, and 
may be had of any optician who deals in foreign goods, or of 
any respectable toy dealer for 1s. 6d.; it can also, without 
fear of injury, be sent post free to any address on payment 
of eighteen postage stamps. 
These Stanhoscopes of French manufacture, being originally 
made as toy microscopes, and very cheap, are, of course, not 
in every instance so perfect optically as is desirable; one half 
of those sold are very good, but the remainder are either im- 
perfect or very inferior. In order that the public might be 
supplied with really good articles, at not too high a price, I 
wrote to a London optician, requesting him to turn his atten- 
