1846.] Coal Ash— Yazoo Marl 295 



another effect, it is not a cause. If there is a want of the in- 

 organic matter in a diseased potatoe, it ought to be shown by 

 analysis; but no one has as yet shown this; and yet the most 

 rational way of treating the potatoe is that which will give it 

 the greatest stamina and vigor. We believe the cause is atmos- 

 pherical, that it is analagous to an epidemic, and that it will, like 

 an epidemic, disappear: but that it will be continued longer by 

 the planting of unsound seed, we have but little doubt. Many 

 too, if our views are right, will maintain that they have discover- 

 ed a remedy, and they may be confirmed in their opinions by the 

 disappearance of the disease; which, after all, may be merely the 

 effect of causes of a different character from those of the sup- 

 posed remedies. 



COAL ASHES. 



Experience has confirmed the supposed utility of coal ashes. 

 We should infer from their composition that they are well adapted 

 to clay lands, though it by no means follows that they will be 

 useless on lands in which sand predominates. 



YAZOO MARL— MISSISSIPPI. 



Our friend and correspondent, J. Ingersoll, has discovered a stra- 

 tum of fresh water marl, upon the Yazoo bottoms, which seem to 

 be made up of unios or fresh water clams. It seems to us that it 

 will be found a valuable substance for fertilizing lands which are 

 deficient in lime and other inorganic matters. It is composed as 

 follows: 



Water of absorption, 1.68 



Organic matter, 4.67 



Silex, 32.91 



Peroxide of alumina, 4.78 



Magnesia, trace. 



49.98 



