298 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



proved nearly worthless, while phosphatic bird dung g-uanos, like some of 

 the best samples from Swan Island, have been proved highly valuable, and 

 can be procured at less than half the expense of that from the Chincha 

 Islands, which is now selling at the extravagant price of $100 per ton. 



Mr. Eli H. Cope, of Westchester, Penn., writes to inquire if Sombrero 

 guano can be made to take the place of bones as a manure. 



To this we answer, yes. It has been made to take the place of stones 

 in building a dock in Connecticut, where a ship load of it was imported for 

 the purpose of taking the place of bones, but experiments proved that it 

 was more valuable for dock building. We think that question is answered. 



Dr. Trimble, of New Jersey, earnestly recommends the substitution of 

 Jersey marl in place of guano. Thousands of acres of land are underlaid 

 with marl, where it can be obtained for one dollar a ton. 



Mr. Carpenter. — I am willing to concede all that is claimed for marl upon 

 the almost barren sands of New Jersey. Upon the coast of Long Island 

 Sound it is of less value than Sombrero guano. It would not even answer 

 for dock building. I approve of the appointment of the committee, but 

 think we ought to be careful not to recommend anything that is not of 

 value to the farmer. 



Professor Mapes. — It is wonderfully valuable upon my sandy farm in 



Burlington county; it is utterly valueless upon my farm at Newark. One 



bushel of ashes is worth a thousand bushels of marl upon that soil. In 



Burlington it beats my own phosphates. It is a great mistake to recom- 



, mend green sand marl as a universal manure. 



Mr. John G. Bergen. — It fails upon Long Island, which is as sandy as 

 New Jersey. The greatest objection to the use of marl is the cost of trans- 

 portation, as it requires some 400 bushels per acre. 



Prof Mapes. — It varies very much in quality. From some of the marl 

 pits, if 30 bushels, after being exposed to the atmosphere for some time, 

 be applied per acre, a very favorable result will be produced. Some marls 

 are improved by mixing with lime, for they contain a considerable propor- 

 tion of copperas, which by the action of lime is changed to gypsum. 



Messrs. Mapes, Pardee and Berti were appointed the committee. 



Prof. Mapes. — Can any one inform us how to restore the heat to an old 

 hotbed ? I have applied fresh manure to the outside of the bed. 



Mr. Wm. S. Carpenter. — I have known spent hops to make a good hot- 

 bed. 



Preparation of Night-Soil. 



Mr. Isaac G. Darlington, Westchester, Pa., writes: 



" I would very much like to hear the opinions of the Farmers' Club on 

 the best plan of preparing night-soil for manure at as early a day as con- 

 venient." 



He also inquires about mixing bone charcoal and gypsum with the night- 

 soil: 



" I tried this plan once, but did not receive the benefit that I expected, 

 although it perfectly deodorized the night-soil." 



Prof. Mapes. — That is not the best way to use bone charcoal — its value 

 is mostly lost unless it is treated with sulphuric acid. The best thing to 



