HORTICULTURAL JOURNAL. 303 



bear ; it sickens, yields an unhealthy crop, and ultimately refuses altogether 

 to grow. 



The plants we raise for food have similar likes and dislikes with those 

 that are naturally produced. On some kinds of food they thrive ; fed with 

 others, they sicken or die. The soil must therefore be prepared for their 

 special growth. 



In an artificial rotation of crops we only follow nature. One kind of 

 crop extracts from the soil a certain quantity of all the inorganic constitu- 

 ents of plants, but some of these in much larger ^proportions than others. 

 A second kind of crop carries off, in preference, a large quantity of those 

 substances of which the former had taken little ; and thus it is clearly seen, 

 both why an abundant manuring may so alter the composition of the soil as 

 to enable it to grow almost any crop ; and why, at the same time, this soil 

 may, in succession, yield more abundant crops, and in greater number, if 

 the kind of plants sown and reaped be so varied as to extract from the soil, 

 one after the other, the several different substances which the manure we 

 have originally added is known to contain. 



So with regard to the organic matter which soils contain. That form of 

 organic food which suits one, may not equally favor another species of 

 plant, and thus, at different times, different species may be most suited to 

 the chemical condition of the same field. 



The management and tilling of the soil, in fact, is a branch of practical 

 chemistry which, like the art of dyeing, lead-smelting, or of glass-making, 

 may advance to a certain degree of perfection without the aid of pure 

 science, but which can only have its processes explained, and be led on to 

 shorter, more simple, more economical, and more perfect processes, by the 

 aid of scientific principles. — Prof. Johnston. 



THE PENNSYVLANIA STATE FAIR. 



The fourth annual fair of the Pennsylvania State Agricultural Society 

 was opened on the 26th of September, on the ground selected for the pur- 

 pose at Powelton, in the 24th Ward. 



This is situated on the west side of the Schuylkill, north of Market street, 

 lying between the Pennsylvania railroad and Bridgewater, and embracing 

 over 21 acres. It is very level and was supplied with water from the reser- 

 voir of the railroad locomotive depot. 



The whole was surrounded by a substantial fence, against the inside of 

 which were erected the stalls for the live stock, the whole of which were oc- 

 cupied. 



