GUANO. 195 



firmly thrust down into the fire, and the spoon laid 

 upon it in such a way that the handle rests upon 

 the brick and the hollow with the guano hangs 

 free above the fire. A piece of cork should surround 

 the extremity of the handle, in order that the hand 

 may be protected when brought in contact with the 

 heated spoon. 



3. Lime Test. Pour a teaspoonful of each guano 

 to be examined into a wineglass, and upon this a 

 teaspoonful of slaked lime ; then add a few teaspoon- 

 fuls of water and agitate the mixture briskly. Lime 

 liberates the ammonia from the ammoniacal salts 

 contained in the guano, in just the same manner as 

 from rotten muck and putrid drainings (page 113), 

 and it escapes ; the more excellent^ therefore^ a guano 

 is, the stronger vnll be the pungent ammoniacal odor 

 which escapes from this guano paste. This test does 

 not indeed possess the accuracy of the preceding, but 

 is still in many cases very convenient on account of 

 its simplicity, and more particularly where it is de- 

 sirable to pass a general and approximate opinion 

 upon the quality of different kinds of guano. Under 

 present circumstances, especially, its utility appears 

 the greater, because bird-manure of intermediate ex- 

 cellence is now of very infrequent occurrence, and 

 commerce presents us for the most part with remark- 

 ably good or remarkably bad qualities, in examining 

 which the lime test can be advantageously used, in- 

 asmuch as the difference in the strength and pun- 

 gency of the odor is really so remarkable, that it 



