156 



CALCAREOUS MANURES— PRACTICE. 



of acid and poor land, will probably remain totally neglected for the next 

 fifty years. It is most probable that this same thick and rich body of marl 

 may be found at many miles' distance on the line of rail-road, and indeed 

 wherever the surface is in the same position relative to the granite range. 

 For taking up marl from any depth, greater than 16 feet, or more than 

 two casts with the shovel will serve for, it will be better to use horse-power 

 applied to machinery. A crane which has been used by Wm. Carmichael 

 Esq., of Q,ueen Ann's county, Md., will serve the purpose. His description 

 of the crane was published in the 'Farmers' Register,' as follows : 



" In your ' Essay on Calcareous Manures,' you give instructions for dig- 

 ging and carting marl. This method I pursued for several years, but found 

 the labor hard on my hands, and tedious. Marl here is generally found in 

 deep ravines or in wet grounds. My operations have been slow, from the 

 difficulty of making firm and lasting ways, and the labor of ascending 

 steep hills. Last winter I made a model, and this spring I built a machine 

 for raising marl, to be worked by a horse. I have been using it to advan- 

 tage, and now send you a draught of it, as it may be useful to those who 

 have wet marl pits like mine. By means of a pump to throw oflf the wa- 

 ter, pits may be worked at a considerable depth ; and even if marl is dry, 

 but lies deep, I think the crane may be used to advantage. I use two boxes, 

 and by means of hinges and a latch the marl is discharged from the bottom. 

 I have double blocks ; the rope passes through the swoop about eighteen 

 inches from the end, and runs down to the post which supports the swoop, 

 and passes through it on a small roller, and in like manner through the 

 next post to the cylinder, to which a reel is attached to increase the 

 motion. The post which holds the swoop and the cylinder, runs on iron 

 pins let into thimbles. The lever is in two pieces, one fastened in the 

 cylinder with a groove at the end, into which the other is let, and secured 

 by a sliding iron clamp. When the marl is discharged from the box, and 

 the swoop swung round over the pit, in nautical phrase, by unshipping the 

 end of the lever, the rope unwinds, and the box descends without moving 

 the horse. The circle in which the horse travels ought to be twenty-one 

 feet in diameter. The second and third posts supported by side braces. 



" The cost of the machine is small, though I cannot make an exact esti- 

 mate. The carpenter who did the work was hired by the day on the farm, 



