BURNING MAKES A DIFFERENCE. Ill 



satisfied that it is worth more than plaster, on grass land or in 

 the potato hill. But when I came to inquire, I found the doctor 

 did not use it for manure. I would like to ask the doctor what 

 he does with the leavings of that. 



Dr. Durfee. I use it to stop the leaks in my retorts, where 

 I make the acid for the print works. 



Mr. Buffinton. Do you use the leavings on your land ? 



Dr. Durfee. It goes in with the wood ashes. There is not 

 a great deal of it. We use it simply to plaster up the iron 

 retorts. It makes a very fine plaster to stop up the cracks where 

 the gas comes out. We can stop them very readily by making 

 this lime into the form of putty and putting it on. In setting 

 our retorts, we use it as we would any lime, — use it around our 

 fire-brick. 



Dr. Nichols. We should always bear in mind this fact, — that 

 there are certain articles which are not to be regarded as plant- 

 food, and other articles which are to be regarded as plant- 

 food. Take, for example, clam and oyster shells. I stand up 

 here and say, that ground clam and oyster shells have no fertil- 

 izing effects upon plants. This gentleman (Mr. Buffinton) gets 

 up and says, " You must have been mistaken, because 1 have 

 gone down to the gas works, and taken the gas lime and put it 

 on my land, and it has had a good effect ! " Now just look at that. 

 The shell lime you get there has been burned ; the carbonic acid 

 has been driven off; it is no longer carbonate of lime. You 

 have now quicklime, and your land is benefited by quicklime. 

 If you had taken those shells before they were burned, pounded 

 them up, and put them on your land, the land would have 

 received no benefit from them. You see they have been burned, 

 and that makes a very great difference. 



Mr. Buffinton. Have you not made the statement that 

 oyster- shell lime was not worth anything ? 



Dr. Nichols. No, sir. It does not matter from what source 

 we get our lime. I do not know that burnt oyster shells are 

 any better than burnt marble. Many of our lands are very 

 much improved by liming. In Pennsylvania they lime their 

 lands very extensively, and I think that there are many of our 

 Massachusetts farms that would be benefited by lime. If you 

 ean get any shell lime from the gas works, I think it would pay 



