Tlie Use of a Simple Microscope. 3 



well ripened seeds, it will be the first consideration that the bul/i. 

 of the sample shall consist of such. The character of these will 

 be at once caught by the eye, and singled out as a prominent 

 feature. A small quantity being taken into the palm of the 

 hand, and a magnify ing-glass, proportionate to the size of the seed, 

 being used, a tolerably fair estimate may be made of the entire 

 sample, and any extraneous substances that are not seed at once 

 detected. 



For the larger seeds a common hand magnifier will be suffi- 

 cient, but for the more minute a much greater magnifying power 

 will be required, at least until the observer shall have become 

 perfectly familiar with the objects ; it is a well known fact that 

 the faculty of recognising minute objects turns in a great degree 

 upon familiarity with them, so that upon intimate acquaint- 

 ance even very minute objects are readily recognised at a mere 

 glance with a common lens. Such an acquaintance, however, can 

 only be gained by the use of higher magnifying powers, hence 

 the compound microscope, to be hereafter described, which 

 answers the purpose both for the low and high powers, becomes 

 an essential requirement. 



In the case of "grass seeds," in which one or more varieties 

 of trefoil are commonly combined with various species of grasses, 

 properly so called, the use of the microscope is important, 

 because much of that which is sold under this name, consists 

 principally of the sweepings of the hay-loft, and consequently 

 is not ripened seed ; and it is only by the aid of a microscope 

 that this can be detected. The first step will be to get rid of 

 the minute seeds* and other small objects by sifting. After 

 this has been done the different kinds of trefoil will be readily 

 made out, but the different species of grass, although varying 

 in size and form, are not easily discriminated, although by prac- 

 tice much may be done. To give a practical illustration of 

 such use of the microscope : — To get at the seed of grass, in 

 order to ascertain whether it be well ripened or not, it will 

 be necessary first to get rid of the " outer husk or chafF-scale," 

 which is the peculiar calyx of grasses and plants allied to them. 

 To accomplish this it will be desirable to have them thoroughly 

 dried by heat, so as to render the chaff brittle, it will then 

 crumble away on being rubbed between the finger and thumb, 

 and leave the seed clean and fit for examination. Damping the 



* A farmer in this neighbourhood sowed several acres with grass, and, to his 

 vexation, the land became covered with the Lychnis Dioica, or Campion, which 

 cost him considerable trouble and loss. He has since expended some twenty 

 guineas in the purchase of a first class microscope, and affirms that this would not 

 have happened if he had previously owned the microscope, adding that it " cer- 

 tulnhj would never happen again." 



B 2 



