CORRESP OXDENCE. 



749 



systematic courses of popular or elementary 

 lectures on natural science in the Academy. 

 The completion of the building will facili- 

 tate and strengthen all the functions of the 

 society in all its departments, and lay the 

 foundation of a workshop in which experts 

 and students may pursue investigations ad- 

 vantageously to science and themselves. 



The progress of the Academy has been 

 always deliberate and unobtrusive. It will 

 so continue until accelerated by enlarged 

 resources. 



To the full extent of its means the Acad- 

 emy encourages original research, gives in- 

 struction to those who seek it, and promotes 

 the diffusion of knowledge. Its doors are 

 never closed against a student or votary of 

 science ; every one is cordially welcome, and 

 given such assistance and facilities as the 

 society has, which are all charitable gifts, 

 benevolently aggregated and preserved here 

 for the benefit of the intellectually hungry. 

 It may be safely conjectured that its useful- 

 ness will increase, pari passu, with the aug- 

 mentation of its pecuniary resources, unless 

 Utopian projects of scientific grandeur and 

 exclusiveness be injected into its policy. 



Observance of that wise and holy pre- 

 cept, suum cuique to Caesar the things 

 which are Ctesar's relatively both to sub- 

 stantial things and mental products, would 

 save us all a world of trouble and vexation. 

 Commending the consideration of this pre- 

 cept to my readers most cordially, I am, 

 Very respectfully, 



W. S. W. RtJSCHENBERGER. 



Philadelphia, August 1, 1876. 



LIMITS OF THE "WESTERN GRASSHOP- 

 PERS' RAVAGES. 



To the Editor of the Popular Science Monthly. 



In The Popular Science Monthly for 

 July I find the statement quoted from 

 Prof. Riley that the southern limit of the 

 locust ravages is the 44th parallel of lati- 

 tude, and the eastern limit the 103d merid- 

 ian. The latitude of this place is 39 52' 

 nearly. As I write, the locusts are flying 

 so thickly as to give sunlight the yellow 

 tinge of dense smoke. Last night, in a sin- 

 gle hour, whole fields of barley were eaten 

 to the ground, and the fields swept cleaner 



than the harvester could have done the 

 work. These ravages to-day extend one 

 hundred and twenty-five miles south of this 

 place, or to latitude 37, and how much 

 farther the news has not reached me. 

 Their appearance here is neither unex- 

 pected nor exceptional. During the three 

 preceding years agricultural products 

 throughout Colorado were almost entirely 

 destroyed, and thousands of farms were 

 financially ruined. They have visited us to 

 a greater or less extent annually for the 

 last twelve years, and their ravages have 

 often extended as far east as Lawrence, 

 Kansas, or two hundred miles east of the 

 line prescribed in the article referred to. 

 Our altitude is 8,300 feet above the ocean, 

 but this is not their limit. A few days ago 

 I was on a mountain-summit, 14,000 feet in 

 height, and there they were flying to the 

 westward, high overhead, in immense clouds. 

 Many plans are resorted to for their destruc- 

 tion. Kerosene dripping slowly upon the 

 water in irrigating ditches is very effec- 

 tive. Traveling machines, filled with fire, 

 passing over the ground like mowers, de- 

 stroy millions ; but when they come in 

 clouds, as to-day, I know of no defense at 

 all adequate. 



I have driven them a hundred times to- 

 day from the little twenty-foot green spot 

 in front of my house, and yet there are as 

 many there as if I had done nothing. For- 

 tunately they are fastidious, and often will 

 not eat grass, potatoes, or oats. 



There is one remedy which I believe 

 would be effective, and that is the preserva- 

 tion of prairie-grouse and other insectivor- 

 ous birds. The number of locusts eaten by 

 prairie chickens and quails is perfectly 

 marvelous. For the destruction of hawks 

 and eagles there should be a reward offered 

 by the State. This would preserve many 

 of the birds ; and heavy fines imposed for 

 the destruction of birds, at any time of the 

 year, would work the rest. 



As long as Colorado, Kansas, and Ne- 

 braska, permit the unlimited slaughter of 

 these, their best friends and preservers, 

 they deserve to suffer from the devastation 

 of the locusts, or grasshoppers, as we call 

 them. Respectfully yours, 



I). C. Collier. 



Central City, Coloeado, August 10, 1876. 



