16 
The subject was further discussed by Mr. EH. GEORGE 
Squier, who referred to another similar spring in San 
Salvador, in which he was strongly convinced that the liquid 
does arise from the excrement of bats. 
Dr. ENDEMANN remarked that Dr. Habel had made no 
reference to bats as having been seen at the Honduras spring. 
Mr. F. CoLttinewoop read a paper on Combustion in 
Compressed Air.* 
The paper was announced rather as a series of notes, than 
as a statement of positive results. The caissons of the Hast 
River bridge gave remarkable facilities for experiment; but 
the observations obtained have been rather incidental, than 
the result of systematic tests. The disengagement of large 
amounts of unconsumed carbon, in the form of smoke, ete., 
was early found to cause so much inconvenience, that experi- 
ments were set on foot for the purpose of obviating it. Col. 
Paine, of the engineering staff, was the first to engage in this 
work, using different kinds of oil, ordinary candles, and 
adamantine “coach” candles, 14 inch diameter. In all cases, 
increased consumption resulted from increased pressure; 
the most careful tests, however, were with the adamantine 
candles, and may be tabulated thus, in their results : 
Time of {Relative 
No. of |Tem-| Absolute consuming}| con- | Square | Ratios of 
Exper-|pera-| pressure 1 lb. of | sump- | root of |sq. roots of 
iment. |ture.| per sq. in. candles. tion. | pressure. | pressure. 
1 80° |Openair15lbs.| 32 hours. | 1- 3°873 1° 
2 80° rt Ail BO OO 1185+] 4°796 1:239 
3 80° 25 “| 254 “ 1:255—| 5-000 1-291 
4 88° |Openair 15 lbs.| 28 hours. | 1° 3°873 1° 
5 88° ES Pe 1°75 6-782 1:751 
The two sets of experiments, Nos. 1 and 4, made at differ- 
ent temperatures, show an increased rate of consumption, as 
might have been anticipated in a warmer atmosphere, 
* Subsequently published in full in the Journal of the Franklin Institute, 
Philadelphla, for May, 1873. 
