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XI. — Analysis of a Marl which, havinrj been used for Manure, 
rendered the subsequent Application of Bones inoperative. By 
Dr. Lyon Playfair. 
To the Secretary. 
Sir, — A considerable time since a " marl " was sent to me by the Coun- 
cil for analysis, the pecuharity of the so-called " marl " being, that it 
might be supposed to exert the same action as bones, as these produced 
no effect where this substance had been applied. I communicated the 
result of the analysis at the time it was made, but regret to find that I 
never ofBcially described it to the Society, altiiough I gave an account of 
it in the last lectures I had the honour to deliver to the Society. 
The substance is, properly speaking, a chalk, for the term "marl" 
necessarily implied the existence of a considerable amount of alumina. 
In the portion of substance sent to me for analysis, there is only about 
one-twentieth of a grain of phosphoric acid in 100 grains, or every 100 
tons of the substance would contain about 224 lbs. of bone earth. As 
this is not a very large proportion, I dare not venture to accede to the 
opinion that its beneficial action, as a manure, is due only to its phos- 
phoric acid ; but to enable you to judge for yourself, I subjoin all the 
constituents in the chalk sent to me for examination. 
Moisture 0*70 
Carbonate of lime . . . . . 95 '50 
Silica (partly united with potash) . . 0'5I 
Protoxide of iron . . . . . 1-70 
Alumina . . . . . . 0-64 
Sulpliate of lime 0*37 
Phosphate of lime (as bone earth) . . O'lO 
Carbonate of magnesia . i . 0'19 
Chloride of sodium . . . . 0'13 
Potash ... . . traces 
Loss on analysis . . . . . 0'16 
100-00 
Sir, I have the honour to be, 
Museum of Economic Geology, Your faithful Servant, 
Itit July, 1845. Lyon Playfair. 
Xn. — On the Application of Liquid Manure to a new variety of 
Italian Rye Grass. By W. Dickinson. 
To the Duke of Richmond. 
My Loud Duke, — I beg to send your Grace a report of my mode of 
cultivating Italian rye grass as food for my horses, the success of which 
has astonished me very much, and which I am anxious to make known 
for the general welfare of agriculturists at large. 
