258 BENJ. PIKK'P, JR., DESCRIPTIVE CATALOGUE. 



Mites, d-c., in Seeds. Various species of mites, and other 

 curious insects, may be found in the siftings of seeds, par- 

 ticularly a very peculiar one, in those of the common poppy ; 

 this insect is furnished with two fangs of a very formidable 

 description, having joints like the claw of a lobster with 

 these fangs it seizes its prey and conveys it to its mouth. I 

 would recommend every person possessing a microscope to 

 provide himself with some of these siftings, which may be 

 procured at any of the seed shops. 



Cheese Mites are those minute creatures found in old 

 cheese. To the eye they appear like moving particles of 

 dust, but the microscope discovers them to be animals, per- 

 fect in all their parts, having as regular a figure, and per- 

 forming all the functions of life as well as those animals 

 which are many million times their size. 



Common Salt, &c. Place a single drop of water in a 

 glass, and put a few particles of common salt in it ; give it 

 a gentle heat till the water is evaporated, and you will have 

 beautiful crystals, in the form of cubes, Epsom salts in six- 

 sided prisms, alum in octagons, crystals of nitre, saltpetre, 

 and green vitriol. To obtain crystals of camphor, place a 

 drop of spirits of wine on a glass, hold it over a candle ; 

 when evaporated, place it on the microscope, and they will 

 be seen. 



Microscopic Chemistry. Another important field of in- 

 quiry by the microscope is chemical action. This opens an 

 endless subject of investigation of a very rich order ; and 

 will probably lead, ere long, in the hands of some talented 

 experimenter, to very valuable results. The mode of pur- 

 suing this class of observations is very simple. Prepare n, 

 few pieces of thin and very flat glass, about an inch long 

 and three quarters of an inch broad. They may be larger 

 or smaller, according as is best adapted to the port-object 

 of the microscope to be used. Some of them should be the 

 eighth of an inch less every way than the others. A variety 

 of chemical agents should be provided in small glass bottles 

 with glass stoppers, and a few glass rods about four inches 

 long, with a rounded end, for the purpose of taking a small 

 drop out of any liquid. These should be kept in a glass of 

 clear water, when they are not actually used, in order that 



