NOTES. 



719 



Testing Lighthouse - Lights. — Experi- 

 ments have been begun by the corporation 

 of Trinity House, at the South Foreland, 

 England, to determine the relative value of 

 the electric, gas, and oil lights as illumi- 

 nants for lighthouses. The two lighthouses 

 already established on the Foreland are il- 

 luminated by electricity, and are known as 

 the high light and the low light. Near them 

 have been erected three experimental light- 

 houses : one, provided with electrical lights 

 that have a total power of 30,000 candles ; 

 a second, furnished with gas-burners, of Mr. 

 AVigham's design, that may give a total of 

 12,000 candles ; and the third, with the oil 

 and gas burners invented by Sir James 

 Douglass, Three stations have been fixed 

 for testing the lights, at distances respect- 

 ively of half a mile, a mile and a quarter, 

 and two and a half miles, at which huts 

 have been fitted up as photometric observa- 

 tories. Measurements will be taken for de- 

 termining the penetrative power of the sev- 

 eral illuminants in different states of the 

 weather, and for ascertaining to what ex- 

 tent the principle of superposition of lights 

 may be applied. One of the questions to 

 be determined is relative to the compara- 

 tive value of a large area of low illumina- 

 tion and a small area of high illumination. 



New Pests in exchange for Old. — The 



Australasian colonies have suffered greatly 

 from the multiplication of rabbits, which 

 were originally introduced there from Eng- 

 land. Now, they are crying out against a 

 plague of dogs, which, increasing rapidly, 

 and semi-wild, have become very destruc- 

 tive to the sheep, and rewards are offered 

 for their destruction. It is proposed to im- 

 port stoats and weasels into New Zealand to 

 put down the rabbits ; but, if this is done, 

 there is danger that the latter estate of the 

 colony will be worse than the present one. 

 The sugar-planters of Jamaica have suffered 

 greatly from the depredations of rats among 

 their canes, and mongooses have been im- 

 ported to destroy them, with apparent gen- 

 eral benefit so far. " But the new importa- 

 tion continues to multiply and spread, not 

 only on sugar-estates, but on the highest 

 mountains, as well as along shore, even 

 amid swamps and lagoons ; and, when the 

 sugar-cane rat is wholly exterminated, the 



mongoose will still go on increasing, and 

 what then ? Must the colonists find some- 

 thing else to exterminate the mongoose, 

 and save their poultry, and so on ad infini- 

 tum ? " As it is, many of the harmless in- 

 digenous fauna of the island are already 

 diminishing under its attacks. 



NOTES. 



Dr. B, a. Gould, of the observatory at 

 Cordoba, Argentine Picpublic, writes to Pro- 

 fessor J. D. Dana that, after fourteen years 

 of absence from his country, he finds himself 

 so near the end of the special work on which 

 he has been engaged that he hopes to re- 

 visit New England in the spring. Four vol- 

 umes of star positions have been published, 

 and a meteorological volume is started on its 

 way. He hopes to leave a mass of similar 

 material for the occupation of his successors 

 in the institutions ; to leave the manuscript 

 of seven astronomical quartos ready for the 

 press ; and to bring with him for publica- 

 tion in the northern hemisphere the " Gen- 

 eral Catalogue of Southern Stars," which 

 will complete the astronomical work. 



Mr. "W. E. Garforth, of Normanton, 

 England, has invented a simple apparatus 

 for detecting fire-damp in collieries. It con- 

 sists of a small India-rubber hand-ball fitted 

 with a protected tube. By compressing the 

 ball and then allowing it to expand in a 

 suspected atmosphere, it becomes filled with 

 the air. It can then be taken to a safe place, 

 and the air can be tested in a lamp. 



Success is claimed to have attended the 

 operation of the system of jetties planted by 

 Captain Eads for deepening the channel of 

 the Mississippi River near its mouth. While 

 there were formerly only from eight to thir- 

 teen feet of water over the bars at low water, 

 the least depth through the jetties was, last 

 May, thirty-three feet, and the channel is 

 steadily wearing itself deeper. 



At the recent meeting of the German 

 naturalists and physicians at Magdeburg, 

 Professor Landois, of Miinster, spoke of the 

 imperfections and comparative uselessness 

 of most zoological gardens, and advised the 

 institution of smaller gardens having well- 

 defined fields of observation and investiga- 

 tion. He cited the successful example of the 

 zoological section of Westphalia and Lippe, 

 whose garden of native beasts yielded an 

 annual surplus. In connection with this is 

 established a zoological museum of the dis- 

 trict, in which the biological side is kept 

 prominent, and which is nearly complete in 

 invertebrates. The section publishes scien- 

 tific lists of the native fauna, and is prepar- 

 ing for a wider circulation a " Westphalian 



