146 — Short Papers and Notes. . 
In looking for inhabitants go out at extreme low tide, and with 
a net scoop up almost anything you can find which has been left 
by the tide. Take the result home and sort it over, culling out 
what you want, and you will be surprised at your varied collection. 
Wbat a Ton of Coal Wields. 
A ton of coal yields about 8,000 cubic feet of gas, and 1,500 
pounds of coke. ‘The purification of the gas furnishes 45 gallons 
of ammonia water, from which is obtained sulphate of ammonia 
for agricultural purposes, and about 130 pounds of tar. It is here 
that the operation becomes especially interesting, for from this last- 
named product are obtained 70 pounds of pitch, 18 of creosote, 
9 of naptha, 13 of heavy oils, 6 of napthaline, 4 of napthol, 2 of 
alizarine, about 1 each of phenol, aurine, and aniline (the sub- 
stance to which we are indebted for such wonderful colours), 10 
ounces of toluidine, 6 of anthracine, and 12 of toluene. Finally, 
it will interest photographers to know that hydroguinon, that 
product which has been so much spoken of lately, and which was at 
first obtained from cinchona, is now obtained from coal by indus- 
trial processes.—La Science en Famille. 
The Bull frog. 
In the Bull Frog (Rana pipiens) the larvee are usually five 
inches long, and take from two to three years to complete their 
transformation. They may be hindered in this and be made to 
take twice that time. In this case the larve may attain seven 
inches in length, but wi!l be tailless. 
Volcanic Fslands. 
According to Murray’s theory, the volcanic islands, whose 
surface is beneath water, are raised by the deposition of calcareous 
matter until they reach the line at which the coral builders can 
work. ‘Then the coral maker builds the reefs which rise gradually 
until they enclose the water in a complete or incomplete ring, and 
so they form a lagoon. Then comes the deposition within the 
ring, of detrited particles worn away from the reef by the waves 
breaking over it, and so the inner channel becomes shallower. 
This is in opposition to the Darwian theory of subsidence. 
A Strange Fight. 
The larva of the water-beetle (Dytiscus marginalis), says a 
