374 AGRICULTURE OP MAINE. 



teaspoon fill of dilute ammonia water, such as can be secured 

 from any druggist. (One should not attempt to use in its place 

 the ordinary, household ammonia, sold for cleaning purposes.) 

 Stir the mixture ooccasionally during the first hour or two. If, 

 after a few hours or by the next morning, the licjuid has taken 

 on a reddish-brown, dark chocolate or black appearance, it 

 is an indication that the soil contains a considerable amount 

 of organic matter which has not been previously neutralized by 

 lime, for where such neutralization has taken place, ammonia 

 will give only a slightly colored extract. This test cannot be 

 depended upon in the case of sub-soils, and it has far less sig- 

 nificance in connection with soils which are quite deficient in 

 organic matter. 



If the litmus paper shows a high degree of acidity, and a 

 copious, dark or black extract is obtained in the ammonia test, 

 the probability is great that lime must be applied in order to give 

 the best results with most agricultural crops. 



KINDS OF LIME TO APPLY. 



In the case of heavy clay and silt soils which bake badly when 

 they become dry, and which are rich in acid vegetable matter 

 (a fact which would be indicated by securing a black extract 

 with ammonia water), ground, burned lime, air-slaked or water- 

 slaked lime may be used, provided they can be secured at eco- 

 nomical prices. In the case of all other soils, particularly if 

 they are light, sandy or gravelly, or inclined to be occasionally 

 dry, finely ground limestone is preferable to any of these other 

 forms of lime. This is for the reason that no immediate ill 

 effects follow its use, whereas, if the other form of lime are 

 applied in any considerable quantity to soils of a naturally dry 

 character, occasional serious ill effects are noticed, which may 

 endure throughout the first season. 



Ground limestone is a favorite form to apply because it is 

 mild instead of caustic. Other forms of lime, because of their 

 caustic or burning character, are very disagreeable and danger- 

 ous when they get into the eyes of the horses or workmen. They 

 are also more powerful in their immediate destructive effects 

 upon the soil humus. 



