The Observatory at St. Martin. 353 



On entering the door, in the centre of the apartment is a transit 

 instrument in situ, for the convenience of using which openings 

 are made in the roof, usually kept closed by traps. This apparatus 

 is not the most perfect of its kind, but is amply adequate for all 

 its uses. On the left is a clock, the works of which, by means of 

 a wheel, are made (while itself keeps proper time,) to move slips 

 of paper along little railways, on which the anemometer by dots 

 registers the velocity of the wind ; the rain guage, the commence- 

 ment and end of showers ; and the wind vane, the continually 

 shifting currents of the wind. This is effected by a pencil, kept 

 applied by a spring to a piece of paper on the dial previously 

 alluded to, and as, by the clock-work, the dial and the two previ- 

 ously mentioned slips of paper move at the rate of one inch per 

 hour, so it is easy to determine, in the most accurate manner, the 

 direction and force of the wind at any hour of the day, or any 

 period of the hour. "With the exception of the clock, the whole 

 of this miniature railway-work, with all its apparatus, wheels, ,&c, 

 &c, is the work of Dr. Smallwood's own hands, and exhibits, on 

 his part, a mechanical talent of the highest order. 



At the extreme end of the room is a table, beneath which is an 

 arrangement for a heating apparatus, and on which is the four 

 arm conductor previously alluded to. To the two lateral and 

 front arms hangs, respectively, two of Volta's electrometers, and 

 one of Bennet's, while beneath the knob on the anterior, there is 

 a discharging apparatus, with an index playing over a graduated 

 scale, to measure during thunder storms the force of the electric 

 fluid, by the length of its spark. On this subject we cannot avoid 

 a reflection on the fate of the unfortunate Richman. In this case 

 such precautions are adopted as will obviate any casualities what- 

 ever ; great precaution, however, is required in these experiments, 

 and Dr. Smallwood, fully aware of it, has the whole placed in 

 connection with the earth by means of a brass chain and iron rod. 

 As another proof of Dr. Smallwood's ingenuity and mechanical 

 skill, we may notice that the whole of this apparatus, even to the 

 electrometers, is the result of his own handicraft ; and the whole 

 arrangements in the little room are a signal proof how much a 

 man may do unaided, and how well he can effect an object when 

 thrown entirely upon his own resources. 



On the right wall of the apartment are suspended the barome- 

 ters, of which there are three. 1. A standard of Newman's; 2- 

 Another of Negretti's, but of different construction ; and 3. One 



