1874.] Vedler—On the Calcutta Coal-Gas. 183 



called ; and N. W. of it, on the Chiramati, lay Paikpara, the place, no 

 doubt, where the Bengal Paiks were stationed. 



3. Contributions towards a Tcnowledge oftJie Burmese Flora, Part I. — 

 By S. KuEz, Esq. 



This paper will be published in the forthcoming number of the Journal. 



4. Descriptions of nine species of Alycceince from Asdm and the Naga 

 mils.— By Majok H. H. Godwin-Austejst, F. G. S., F. Z. S. 



This paper will be published in the Journal Part II. 



5. Note on the Composition of the Calcutta Coal-Gas. — -By" Alexander 

 Pedlee, F. C. S., Fellow, Chem. jSoc, Berlin. 



The bad quality of the gas supplied to Calcutta is the subject of very 

 frequent remark, and judging from the amount of light furnished by most 

 of the public gas lamps, it would be by no means an unfounded one. There 

 is however, no doubt that the burners supplied to these lamps are so badly 

 constructed, that they are not capable of giving anything like the maximum 

 amount of light which should be produced by the gas. The returns of the 

 official Gas Examiner for the past year, shew that the average illuminating 

 power of the gas, when burnt at the rate of 5 cubic-feet per hour from a 

 standard argand burner, equalled the light of 13 sperm candles burning 

 120 grains per hour ; and he has also shewn that the generality of the street 

 gas-lamps do not give a light equal to more than seven or eight candles. 

 It would be obviously unfair then to condemn the gas because of the bad- 

 ness of the light of the street lamps. 



A coal-gas which only gives a light equal to thirteen candles is, how- 

 ever, of very poor quality, for very few large towns are satisfied with a gas 

 giving less than sixteen candles, the minimum now allowed in London. 

 There is no doubt that the large quantity of ammonia which is present in 

 the gas of Calcutta, and which has averaged during the past year 37*5 

 grains per 100 cubic feet, must deteriorate its illuminating power to some 

 extent, and there is also no doubt that this is the cause of the excessive 

 fouling of the gas-pipes, fittings &c., which is a frequent source of annoy- 

 ance, and which may also produce a further decrease in the illuminating 

 power of the gas. 



Judging, however, from the composition of the various samples of In- 

 dian coals, such as are obtained from Sanktoria, Dumarkanda, Raniganj, 

 Banali and Mangalpur, the analyses of which have been published by the 

 Geological Survey, there did not appear to be any reason, why illuminating 

 gas of a very fair quality should not be obtained from them, if properly 

 treated. It appeared to me to be very probable that the low illuminating 



