59 



If males are nol: attracted at the first display it is repeated, at 

 short intervals, for three or four times. 



In nature, the worm is not phosphorescent after the mating, 

 apparently. In confinement, a dull phosphorescence may be pro- 

 duced by disturbance for an hour or more. 



This phenomenon makes it possible to study the embryology of 

 the species with exactness. 



SOME PROBLEMS CONNECTED WITH THE COALS 

 OF ILLINOIS. 



S. W. Parr. 



I. Weathering of Coal. 



Summar}' of results : 



(a) Submerged coal does not lose appreciably in heat value. 



(b) Outdoor exposure results in a loss of heating value vary- 

 ing from 2 to 10 per cent. 



(c) Dry storage has not advantage over storage in the open 

 except with high sulphur coals, where the disintegrating effect 

 of sulphur in the process of oxidation facilitates the escape of 

 hydrocarbons or the oxidation of the same. 



(d) In most cases the losses in storage appear to be practically 

 complete at the end of five months. From the seventh to the 

 ninth month, the loss is inappreciable. 



(e) The results obtained in small sam.ples are to be considered 

 as an index of the changes affecting large masses in kind rather 

 than in degree, but since the losses here shown are not beyond 

 what seems to conform in a general way to the experience of 



