150 OPERATIONS OF TILLAGE. 



Finally, a heavy roller is of great advantage to grass- 

 grounds in the spring, by reducing irregularities of surface, 

 and pressing down the plants or earth which have been 

 thrown up by the frost. 



There are also rollers constructed for other purposes, as 

 the spiked roller^ which is used to pulverize stubborn clays 

 preparatory to the wheat crop, and to scarify old mead- 

 ows and pastures, as a means of renovating them, and of 

 covering the seeds of grasses which may be sown thereon. 

 Ohhis descvipiionisConcklin^s press-harrow, fig. 34, and 

 a somewhat similar implement invented at Washington. 

 The common spiked roller is formed by inserting several 

 rows of spikes, of cast or wrought iron, in a common hard- 

 wood roller. The concave, or scalloped roller, is adapt- 

 ed to the form of ridges, and a small one is often at- 

 tached to the horse turnip-drill. 



§ 5. The Cultivator. 



There are now various implements in use denominated 

 Cultivators, similar in their use, and frequently resembling, 

 in their construction, the horse-hoes of Europe. They 

 are particularly serviceable in the culture of Indian corn, 

 Swedish turnips, beans, and other row and drilled crops, 

 as a substitute for the plough. By passing this imple- 

 ment frequently between the rows, the ground is kept 

 free from weeds, and in a fine state of pulverization, while 

 the manure and vegetable matter of the sod, which have 

 been buried by the plough in preparing for the crop, are 

 left below, where they are most efficacious, and the roots 

 of the plants are preserved from injury. The cultivator 

 should be passed through a hoed crop twice at a dres- 

 sing, and if the soil be stiff or grassy, it may be passed 

 oftener, or repeated at short intervals. The teeth are 

 of various forms, according to the purpose for which they 

 are used. One of these forms is shown in fig. 37. It 

 is most convenient to have teeth of different kinds, for 

 instance, such as are fitted to skim the surface, and de- 

 stroy weeds — others to break up and pulverize the sur- 

 face ; and others, again, to gather the roots of quack and 

 other perennial pests. One of our neighbors has been 



