307 



Army worms. — Ravages of insects bearing this name are reported in 

 Pike and Posey Coimtles, Indiana, in White Connty, Illinois, in Jeffer- 

 son County, Iowa, and in i^evada County, California. 



CniNcn-BUGS.— The chinch-bug ^Yas destructive in Madison, Lawrence, 

 Washington, Perry, Clinton, Clark, Crawford, and Eflinghani Counties, 

 Illinois; in Polk, Jefferson, St. Clair, Lewis, Marion, Montgomery, Rey- 

 nolds, Vernon, Harrison, Perry, Iron, Dallas, and Johnson Connties, 

 Missouri; in Bourbon, Franklin, Miami, Osage, and Coffee Counties, 

 Kansas, and in Thayer, and Nemaha Counties, Nebraska. 



Miscellaneous.— White grubs are complained of in Rhode Island, 

 and Michigan; rose-bugs injured the grapes in Middlesex County, Con- 

 necticut. An unknown wheat Hy is reported in Mechlenburgh County, 

 Virginia. The wheat midge is reported in Putman County, ^\''est Vir- 

 ginia. Canker and measuring worms did great injury to the fruit in 

 Delaware County, Ohio. In Lucas County, Iowa, an unknown insect 

 seriously damaged the grapes and even killed the vines. 



CHEMICAL MEMORANDA. 



By Eyland T. Brown, Chemist. 



Examination OF marls. — The marls which are associated with the 

 tertiary belt lying between the Alleghany Mountains and the Atlantic 

 coast are of more importance to the agriculture of the country than has 

 been recognized heretofore. They consist of an accumulation of the re- 

 mains of marine animals, chiefly shell-fish, closely allied to the si^ecies 

 now existing in the neighboring bays and estuaries. Sometimes, how- 

 ever, the teeth of the shark are found in a good state of preserva- 

 tion.. These remains are commonly imbedded in a very fine sand, 

 which, on first exposure to the air, has a dark green color, but, on dry- 

 ing, becomes an ash gray or light lead color. These beds vary in thick- 

 ness from a few inches to 10 or 12 feet. In most of these the remains 

 have not undergone petrifaction, though the animal matter appears to 

 have been almost entirely removed. In consequence of this most of the 

 shells will crumble into powder on exposure to the air. The amount of 

 organic matter in these marls is, therefore, very small, but nearly all 

 the mineral elements of these ancient organisms remain in a form which 

 can be made available in the production of crops. 



The phosphoric acid is chieflj^ in combination with lime as a neutral 

 phosphate, and consequently is insoluble ; but the disintegration of the 

 shells reduces it to- so fine a state of division that the phosphate, under 

 the influence of carbonic acid, passes slowly into an available form. A 

 portion, however, of the i^hosphoric acid is in combination with iron, 

 from which it is readily liberated in the presence of potassa or lime. 



The alkalies (chiefly potassa) are in combination with silica and iron, 

 forming a double silicate of potassa and iron which is insoluble in wat«r; 

 but, on exposure to the air, the compound is broken up bj^ the iron pass- 

 ing into the form of a peroxide, the remaining elements being resolved 

 into silicic acid and soluble silicate o,f potassa, which is available for 

 the use of crops. 



The supply of marl in the belt above alluded to appears to be practi- 

 cably inexhaustible ; but the quality differs materially in the different 

 beds even in the same vicinity, as will be seen by the following : 



