310 



MONTHLY JOURNAL OF AGRICULTURE. 



edge C D be applied to the ruler A B, and, being 

 attached thereto, let the paper be rolled round 

 Fig. 7 the ruler; the ruler will then present the 



A. appearance of a screw, fi^'. 7, the thread 

 I of the screw being marked by the black 



line C E, winding continually round the 

 ruler. Let D F, tig. 6, be equal to the cir- 

 cumference of the ruler, and draw F G 

 parallel to D C, and G H parallel to D E, 

 the part C G F D of the paper will ex- 

 actly surround the ruler once : the part C 

 JG will form one spire of the thread, and 

 I may bo considered as the length of one 

 J inclined plane suiTounding the cylinder, 

 "il C H being the corresponding bight, and 

 iG H the base. The power of the screw 



B. does not, as in the ordinary cases of the 



inclined plane, act parallel to the plane or thread, 

 but at right angles to the length of the cylinder 

 A B, or, what is to the same efFect, parallel to 

 the base H G ; therefore the proportion of the 

 power to the weight will be, according to prin- 

 ciples already explained, the same as that of C 

 H to the space through which the power moves 

 parallel to H G in one revolution of the screw. 

 H C is evidently the distance between the suc- 

 cessive positions of the thread as it winds round 

 the cylinder ; and it appear.s, from v^hat has been 

 just stated, that the loss this distance is, or in 

 other words, the finer the thread is, the more 

 powerful the mackine will be. 



1^^ The action of the Screw will be illustra- 

 ted in our next. 



PEA CULTURE IN THE SOUTH. 



WHY IS IT NOT EXTENDED OVER VIRGINIA, AND INTRODUCED IN MARYLAND ? 



Planters of the best judgment in Carolina, 

 look upon the culture of Peas as one of the most 

 practicable and powerful auxiliaries in every 

 system for the improvement of worn out lands. 

 We have been indulging the hope of a commu- 

 nication on the subject from a gentleman of 

 South Carolina, whose name is associated there, 

 with whatever is proposed with a view to Agri- 

 •ultural improvement. From him we might 

 expect a clear account, not only of the mode of 

 culture and how it is brought to do its part in 

 the general system, for immediate profit and 

 ultimate improvement, but to be favored also 

 with his opinion — alwaj's entitled to respect — 

 as to its action. The theoi-y, we believe, is that tlie 

 pea draws its support, ijke clover, chieflj' from 

 the atmosphere, and that plaster of Paris has the 

 same effect on both. We are well convinced 

 from what we have heard that large districts of 

 country, north of the region within which field- 

 pea culture is practiced with great benefit, are 

 losing much precious time and a valuable re- 

 source, in postponing their inquiries into, and 

 adoption of that auxiliaiy to their plans for im- 

 proving their fanns. Until we get fuller and 

 Kiore exact information, we give the following 

 from the last Southern Agriculturist : 



There is perhaps no section of countiy in the 

 ttpper districts, which has improved more in 

 Agricultural condition than the " Old Pendle- 

 ,toa" neighborhood — the result, we are told, of an 

 Agricultural Society, composed of intelligent 

 and practical farmers. We were struck with 

 the manifest improvement in the breed.s of cat- 

 tle and hogs. The Berkshire cross has here 

 told w^ell — for the very simple reason, we pre- 

 sume, that stock is attended to. We have 

 never seen a finer stock of hogs, in travel- 

 ing through any country. More attention seems 

 to be paid to the pea culture hei'e, than in any 

 section we have been. We are told that it is 

 the opinion of many good fanners hereabouts, 

 that land can be improved to a high degree, by 

 (010) 



the pea culture. We have no doubt of the fact, 

 if properly applied. Tliere is a pea. the Chick- 

 asaw pea, which bears most abundantly, and 

 once planted, is almost inextirpable. We have 

 seen it put into com ground — after the corn was 

 taken off — pastured by the cattle and hogs all 

 the winter — in the spring put in oats, and after 

 the oats ^vere taken oft", the pea came up in great 

 abundance. Now suppose these were to be let 

 alone, and in lieu of the absurd sy.stem of pas- 

 turing stubble, the vine and stuhlde should be 

 turned under in the fall — would not the laud be 

 vastly improved ? We have no doubt — if the 

 pea were sown on our stubble lands — a peck to 

 the acre — and the crop turned in while in the 

 bloom — that the effect produced would be equal 

 to the best clover ley, .so much esteemed in 

 Virginia and at the north. It is an admitted 

 fact, that leguminous plants exhaust a soil in a 

 very slight degree. 



The pea vine contains about 53 per cent, of 

 potash, a most important ingredient in all .soils, 

 for the production of grain or cotton. If this 

 should be returned to the soil, in addition to the 

 carbon and nitrogen contained in the vine, it 

 seems to me that there would be a manifest im- 

 provement. It has been discovered by analysis 

 that cotton wool contains potassa 31.09 per 

 cent.; lime, 17.05; magnesia, 3.26; phospho- 

 ric acid, 12.30: sulphuric acid, 1.22. That the 

 .seed contains phcsphoric acid, 4.5.85; lime 

 29.79; potassa, 19.40; sulphuric acid. 1.16 per 

 cent. While corn contains potassa 20.87; phos- 

 phoric acid. 18.80; lime, 9.72; magnesia, 5.76 

 per cent. The following analysis of straws may 

 not be uninterestins : 



From the foregoing data we learn tliat potash 



