POPULAR MISCELLANY. 



855 



ter of a metallic diaphragm. This arm or 

 bar is a lever, and multiplies the scope of 

 vibration. The current which is transmit- 

 ting a message vibrates the diaphragm. In 

 proportion to the strength of the wave of 

 electricity on the wire, the friction between 

 the arm and the cylinder is varied, and the 

 amount of sound produced is varied in like 

 proportion. The sound transmitted is thus 

 magnified. The person who talks furnishes 

 the power, but the person who is at the re- 

 ceiving instrument controls the power, and 

 the message only becomes audible when the 

 chalk cylinder is rotated. This receiving 

 instrument has no connection with the 

 wires that transmit the message, owing to 

 defects not yet overcome in the manufac- 

 ture of telegraph wires. It takes its mes- 

 sage through a coil placed in close prox- 

 imity to a second coil which is in commu- 

 nication with the ordinary telegraph wire. 

 Could the coil be dispensed with, the sounds 

 could be still more magnified than they are 

 with the present arrangement. The instru- 

 ment exhibited was only an experimental 

 model ; nevertheless it transmitted messages 

 which were heard by the whole audience, 

 numbering fifteen hundred persons. 



Experiments on the Living Brain. At 



the close of one of the daily sessions of the 

 Association, Professor Burt G. Wilder gave 

 illustrations of some of the experiments 

 of Ferrier on the brains of living animals. 

 Having by the use of ether reduced a cat 

 to the state of insensibility, Professor Wild- 

 er laid bare the surface of the animal's 

 brain by removing the roof of the skull. 

 On the wall was hung a diagram of the 

 brain, with certain regions of it designated 

 by figures. A chart stated what move- 

 ments would be made by the cat, as these 

 different regions of its brain were succes- 

 sively touched by the terminals of a weak 

 electric current, and in every case the 

 movements occurred precisely as laid down 

 in the chart. Thus, when the place on the 

 brain answering to that marked " 1 " in the 

 diagram was touched, the opposite hind-leg 

 of the animal was advanced as the chart 

 said it would be. When "4" was touched 

 the opposite fore-leg moved as if to strike, 

 being first drawn back. Again, the animal 

 was made to scream, spit, and lash its tail, 

 by similar means. 



Insect-Destruction of Evergreen-Trees. 



Professor S. H. Scudder gave to the mem- 

 bers of the Entomological Club, an annex 

 of the Association, an interesting account 

 of the destruction of the pine-forests of 

 Nantucket Island. Formerly, he said, the 

 island was well wooded ; but, during the 

 war with England in 1812, the inhabitants, 

 cut off from intercourse with the mainland, 

 were reduced to such straits for fuel that 

 they burned every tree. Some years ago 

 plantations of pines were begun, and now a 

 large portion of the island is covered with 

 pines and scrub-oaks. Now, however, sure 

 though slow destruction threatens the young 

 forest through the agency of a small moth, 

 whose larvae attack the leaf-buds. This 

 moth is closely allied to the Retinea silves- 

 trina of Europe, but probably belongs to a 

 distinct species. It bores into the tip of 

 each terminal bud, and saps the life of the 

 tree. Every pine on the island, Mr. Scud- 

 der says, is affected, and he sees no way to 

 save the forest. Other members reported 

 the pi^esence of Retinea apd allied species 

 of insects in different parts of the country. 

 Professor J. H. Comstock had found a large 

 species of Retinea destroying pine-trees in 

 western New York. Mr. Bassett said that 

 a few years ago the white pines and Norway 

 spruces in Connecticut were threatened with 

 destruction by a moth, but the danger passed 

 away. Professor Riley said that the juni- 

 pers on Long Island are attacked every- 

 where by a destructive moth, and that all 

 the foreign imported evergreens suffered in 

 like manner. He recommended the use of 

 Paris-green as a means of exterminating the 

 pests. 



The Constitution of the Snn. Professor 

 S. P. Langley, Vice-President, addressed Sec- 

 tion A upon the progress of solar physics. 

 Even after the invention of the telescope, he 

 said, astronomy was more concerned with 

 the motions of the heavenly bodies than 

 with their physical nature. With the aid 

 of mathematics, the great law of gravitation 

 was ascertained, and the movements of the 

 heavenly bodies thenceforth could be pre- 

 dicted. But great questions still remained 

 untouched. Life on 'the earth depends on 

 the great central fire, the sun. What is 

 that fire ? What are its sources ? How 

 long will it continue ? With almost the sole 



