1885-86.] Edinbjirgh Naturalists' Field Club. 273 



the map supplied gratuitously by another of our citizens, Mr 

 Bartholomew. 



In conclusion, let me urge upon you all to use your best efforts 

 to proclaim from one end of the city to the other, and if possible 

 far beyond its boundary, the advantages to be derived from the 

 membership of the Field Club. With more members we would 

 have greater resources, be able to make our meetings more attrac- 

 tive, and do better work. The measure of prosperity that has 

 attended the Club within the last few years may well encourage 

 us for the future ; and need I remind you that " nothing succeeds 

 like success." 



II.— TEE OEGANIG CAUSES OF THE COLORATION 

 OF WATER, Etc. 



By Mr JOHN RATTRAY, M.A., B.Sc. 



(Read Nov. 20, 1885.) 



The explanations that have been given of unusual colours of 

 water, snow, hail, &c., may be arranged in four periods, more or 

 less distinct from and independent of one another — viz. : (1) The 

 theocratic, or period of wonder ; (2) the hippocratic, or period 

 of doubt ; (3) the naturalistic period ; (4) the cosmic period. To 

 the first of these periods must be assigned the opinions held by 

 the ancient Greek and Eoman classics, who, from the time of Homer, 

 referred such phenomena as are now familiarly known as blood- 

 rain to the direct intervention of the gods, in modifying the ordi- 

 nary course of the laws of nature. To the second Cicero probably 

 belongs, as by him supernatural interference was, for the first time, 

 doubted, and an attempt was made to obtain a physical explana- 

 tion. Peiresc founded the third period, and Cladni the fourth. 



Prior to Cladni, various remarkable occurrences had taken 

 place ; but in not a iew cases precision is not to be found in the 

 stories that have been recorded. Thus, rivers had suddenly become 

 red without previous red rain — e.g., in Picenum, 323 b.c. In the 

 summer of 586 a.d., a similar event occurred in the Gulf of Venice ; 

 while Pliny records that a lake in Babylon remained red for eleven 

 days. Dew, rain, snow, and hail had been observed to fall of a red 

 colour ; a blood-like moisture, according to Livy, had covered the 

 statues even of the gods and of implements of war. Red snow and 

 hail had fallen, and instances of the occurrence of places suddenly 

 covered with a blood-like mucilage were not unknown. But in all 



