352 The Observatory at St. Martin. 



ART. XXX. — The Observatory at St. Martin, Isle Jesus, Ca- 

 nada East. Xotes by Prof. Charles Smallwood, m. d. 

 ll. d. Read before the Canadian Institute, 20th February, 

 1858* 



The following sketch of the general appearances of the building 

 and instruments, from the pen of Dr. Hall, of Montreal, furnishes 

 a very suitable introduction to Dr. Smallwood's account of the 

 Observatory established by him at St. Martin, Isle Jesus. 



A small wooden building, distant about twenty yards from the 

 dwelling house of Dr. Smallwood, contains the whole of the appa- 

 ratus which has for many years furnished such valuable results. 

 A short distance from it, and on a level with the ground, is the 

 snow gauge. Immediately in front of the entrance to the small 

 building is a dial, with' an index to point out the course of the 

 clouds. Contiguous to the building again may be seen four erect 

 staffs. The highest of which — 80 feet — is intended for the ele- 

 vation of a lighted lantern, to collect the electricity of the atmos- 

 phere, the copper wires from which lead through openings in the 

 roof of the building to a table inside, on which a four-armed insu- 

 lated conductor is placed. The lantern is made to ascend and 

 descend on a species of railway, in order to obviate all jarring. 

 On another pole is placed the wind vane, which, by a series of 

 wheels moved by a spindle, rotates a dial inside the building 

 marked with the usual points of the compass. Another staff, 

 about 30 feet high, contains the anemometer, or measurer of the 

 force of the wind, which, by a like arrangement of apparatus, is 

 made to register its changes inside. The last pole, 20 feet in 

 height, contains the rain guage, the contents of which are con- 

 ducted by tubing also into the interior of the building, in which, 

 by a very ingenious contrivance, the commencement and ending 

 of a fall of rain are self-marked. 



At the door entrance on the right side is a screened place, ex- 

 posed to the north, on which the thermometer and wet bulb 

 thermometer are placed, four feet from the surface of the earth. 

 A similar apartment on the left contains the scales with which 

 experiments are conducted throughout the winter to ascertain the 

 proportional evaporation of ice. 



* From the Journal of the Canadian Institute. "We are indebted to 

 its Council for the use of the wood engravings. — Eds. 



