98 Address. [Feb. 



On the other hand, the minima are usually in April or May. Taking 

 the means of the six minima recorded and comjmring them "with the 

 corresponding shade temperature at the surface, we have a mean mini- 

 mum earth temperature of 73 - 94° F., against a mean surface shade tem- 

 perature of 9T97°. The minimum earth temperature at 25*6 feet, of 

 which records are given, is 73 - 50°, in May 1887, and the maximum 77 , 33°, 

 in October 1884. The minimum mean surface shade temperature 

 during the same period was 59 '79°, in January 1887, and the maximum 

 98-66°, in May 1887. 



The common practice up-country of building taikhanas under houses, 

 and excavating chambers about deep wells, as one often sees in Central 

 India and Rajputana, with the object of having these chambers warm in 

 winter and cool in summer, is thus found to agree with scientific obser- 

 vation. 



Baerisal guns. — Babu Graur Das Bysack has again called the atten- 

 tion of the Society to the peculiar explosive sounds, occurring about the 

 Sundarbans, and known as the " Barrisal guns." A memorandum, giving 

 an abstract of the information recorded on the subject, was drawn up 

 by me and read at the March meeting. A considerable amount of 

 interest was evinced in the subject and a Sub-Committee was appointed 

 to investigate it anew. The Sub- Committee drew up some rules for ob- 

 servers and circulated them, with the memorandum, to the Meteorological 

 Offices, Marine authorities, District officials, and other persons likely 

 to be able to afford assistance and information. Numerous replies have 

 been received, bat as yet nothing to show definitely the cause of these 

 mysterious sounds. The observations will be examined and collated 

 immediately and laid before the Society. One of the most suggestive 

 communications on the subject is a letter from Mr. Manson of Chittagong', 

 who, among other likely causes for the sounds, suggests that they may 

 be caused by the breaking in of the dry crust of mudbanks, due to the 

 washing out of the soft semi-fluid mud beneath, and the sudden escape 

 of the imprisoned air ; the sound thus produced being multiplied by 

 echoes. Valuable observations were also sent in by Mr. Waller, the 

 Collector of Jessore and by Dr. Crawford, Civil Surgeon, Barisal, also 

 by Mr. Elson, of the Pilot Service. 



Chemistry. 

 Reviewing the progress of chemistry in India during the year we 

 find no records of pure chemical research. In applied chemistry, which 

 perhaps in some ways is more important, good work has been done. 

 The vast and, until within comparatively recent years, unexplored field 

 which India affords for investigation on the chemical, and other valu- 



