142 REPORT — 1844. 



A copper dish (vide fig. 1 .) of 3 feet 6 inches diameter and about 6 inches 

 deep, quite smooth and with a Mcll-rounded ring on its edge, lias therefore 

 been very recently mounted upon one of our usual insulators, and we hope to 

 observe some circumstances worth notice with this apparatus w hen we have 

 time to pursue investigations of this kind. 



9. Storm Clock. 



It has been remarked in our MS. Journal that the difficulty of noting 

 down the various and transient phaenomena of a storm is too great for any 

 single observer to overcome without eissistance. 



I have therefore projected a time-piece carrying an index down a long 

 page of paper in half-an- hour, by which means, in lieu of having first to read 

 the times by our chronometer and then to set them down, erroneously per- 

 haps (in the hurry of the moment), the observer will have only to record the 

 events as fast as they occur (nearly) opposite to the point of the index, if he 

 can (for even this will be sometimes too much for one person to accomplish : 

 Beccaria employed several observers frequently on such occasions). 



This instrument is in progress. 



10. New Coulomb Electrometer. 



Tn my " plan," &c. sent to INIr. Wheatstoue in November 1 84'2, is described 

 a proposed modification of Coulomb's electrometer, which seemed to possess 

 great advantages for atmospheric electricity, and I constructed a rough kind 

 of model which clearly showed that the project was feasible. 



The principle consists in suspending a conducting moveable needle in lieu 

 of the usual insulating needle, by a torsion toire, or by a pair of torsion wires 

 (instead of INIr. Snow Harris's silken threads) in such manner as to be always 

 in perfect conducting communication with a. fixed conducting needle. 



A drawing for a complete instrument of this kind was placed in the instru- 

 ment-maker's hands in May. It is now nearly finished. 



11. Spring Anemometer. 

 In order to know something about the force of the wind by simple inspec- 

 tion and without leaving the observatory, we have fitted a little slider to the 

 part (A) elongated of fig. 17, which slider is made to rise or fall by the action 

 of the wind on a set of flyers situated on the top of the wind vane, and by a 

 spiral (volute) spring, &c. ; but this arrangement is not yet complete. 



Kew Observatory, Sept.25th, 1844. 



