346 STATE HORTICULTURAL SOCIETY. 



what it is good for." The effort will be made to answer these questions 

 in this bulletin. 



The whitish deposits found in the bottoro of shallow lakes and ponds, 

 in a loose form which readily mixes up with the water to form a mushy 

 mass; and the more solid and chalky masses found at the bottom of muck 

 beds, sometimes like putty in texture while wet, but becoming crumbly 

 like chalk when dry, and often containing small shells, are marl. 



• COMPOSilTION. 



The marls found in this state consist of carbonates of lime and mag- 

 nesia, oxide of iron, organic matter, and variable quantities of sand and 

 clay. The most abundant and valuable material is carbonate of lime. 

 The marl often contains small quantities of potash and soda, and occa- 

 sionally phosphate of lime. These add to the value of the marl as 

 manure, and a marl in Otsego county that contained one and a half per 

 cent, of phosphate of lime was found to greatly promote the growth of 

 crops when liberally applied to the soil. 



TESTING MARL. 



Tbe essential material in marl is the carbonate of lime, with a less 

 amount of carbonate of mangesia. When any strong acid is poured over 

 marl, the carbonates are decomposed and the mixture will foam up, the 

 same as a mixture of cooking soda and vinegar, the effervescence being 

 caused by the escape of carbonic acid. If a material supposed to be marl is 

 placed in a strong acid and there is no foaming or efferveecence, it shows 

 the asbence of carbonates, and the material is not marl, but most probably 

 is clay. 



A cheap and good method of testing marl is the following: Muriatic 

 acid can be found in all drug stores, and it should be sold for not more 

 than ten cents per pound, as its first cost is less than three cents. Pour a 

 fluid ounce (about a wineglassful) of this acid into a quart fruit jar, or 

 large bowl, and add two ounces of water; into this dilute acid pour a 

 teaspoonful of the powdered marl, and notice the foaming. If it foams 

 up briskly it is marl and probably of good quality. If it dissolves com- 

 pletely it contains no foreign matter and is of excellent quality. 

 If it contains any sand this will be seen at the bottom of the jar and easily 

 recognized; if the marl contains clay or organic matter a gray scum will 

 appear on the top of the foam, and when all chemical action has ceased, 

 a cloudy mass or fine mud will gather at the sides of the jar or sink to the 

 bottom. A small amount of clay will make a large showing of this muddy 

 mass, and may thus mislead the farmer in regard to the value of his muck. 

 A better estimate can be made by observing the amount of foaming. 



For testing marl the muriatic acid, or nitric, is much better than sulphuric 

 acid or oil of vitriol, because they form soluble salts, while sulphuric acid 

 forms the insoluble sulphate of lime or gypsum. 



Where muriatic or nitric acid can not be obtained, strong vinegar may 

 be used, putting a teaspoonful of the marl into a tumblerful of vinegar 

 placed in the fruit jar without diluting it with water. This testing with 

 acids should not be made in metallic vessels. 



