Page:Popular Science Monthly Volume 7.djvu/389

Rh observed 4 times by the Herschels." In short, we know something about this Nebula. Interpreting the entry from the "Double Star Catalogue," we find about No. 2052 that it is No. 698 of Sir John's previously published list; that it has been observed by no one else; that its Right Ascension for 1830 is 5h 13m 488; its North Polar Distance is for the same epoch 89° 6'; and that the precessions in Right Ascension and North Polar Distance are for the same epoch + 38.09 and - 4".02 respectively.

There is not a word about the relative magnitudes of the component stars of the double star referred to, not a word to show whether it is double, triple, quadruple, or multiple, not a word about the position, angle, and distance of the component stars of the double (if it is a double), and finally, not a word about the colors of the components. In short, we know next to nothing about this star. The little we do know is this: 1. Its position in 1830, and we have the means of determining the position with tolerable accuracy at present; and, 2. We know where to look in Sir John's partial "Catalogues," which are scattered through many volumes of the Royal Astronomical Society's "Memoirs," the observations at the Cape of Good Hope, etc., for the information regarding position, distance, color, and magnitude, which is precisely what we require, and which is precisely what is omitted from this new "Catalogue." Thus we may estimate its value to be that of an extended index to various double-star observations, with the approximate positions of these stars. After what we have said, it is unnecessary to go further. Any one can see that to the astronomer this "Catalogue" is of but slight value, while to the average double-star observer (who often has not the means of determining accurately star-positions) it is tantalizing and almost useless. When he finds a double star, how is he to know whether it is new or not, except by going over much of the same work that has been done once by the computer of this "Catalogue?" In fine, this book can only be considered to be truly useful when it is accompanied by the "Memoirs" from which the materials were originally drawn. The publication is not creditable to the Royal Astronomical Society, to the memory of its distinguished projector, nor to its able editors. These gentlemen might well have consulted the work of Dr. Anwers on a similar subject, "William Herschel's Verzeichnissen von Nebelflecken und Sternhanfen, bearbeitet von Arthur Anwers, 1862," for a model as to the way in which the memory of a great astronomer should be honored, and as to the manner in which alone it is worth while to do astronomical work.

this volume (published April 1st) Prof. Riley specially considers six insect-pests, viz., the Colorado potato-beetle, chinch-bug, apple-tree borer, canker-worm. Phylloxera, and the Rocky Mountain locust, improperly called grasshopper. Mr. Riley gives the results of his observations and inquiries during the past year on each of these different insects, and, as in all his previous reports, keeps steadily in view the great practical object of his research, namely, the discovery of the best and most effectual means of annihilating these enemies of agriculture. In Missouri the farmers now accept the presence of the Colorado beetle as the necessary concomitant of the culture of the potato; but they do not fear it as once they did, being provided with the means of keeping the pest in check. Prof. Riley has, for years, recommended the use of Paris green in the war of extermination against this beetle, and the farmers of Missouri now very generally employ this substance, and with the best results: in short, it is by far the cheapest and most effectual means of destroying the beetle. "But, then, Paris green is a deadly poison, and therefore its use causes more mischief by far than could ever be done by the Colorado potato-bug." Prof. Riley, however, speaks from experience, and he asserts that there is no danger to be apprehended from the use of Paris green, "except through carelessness and exposure to its direct influence." Millions of bushels of potatoes were last year grown in Missouri, and great quantities of Paris green used in sprinkling the leaves of the growing plants, and yet the author has not heard of a single case of poisoning, save where people had