Electro-atmospherical Jpparatus, 65 



reading and opportunities of investigation, may see one source 

 from whence we can detect the fallacious evidence of the old 

 poetic writings in matters of philosophy. 



I am, sir, yours, &c. 

 Clapton, Dec. 9, 1816. ThomaS FoRSTER. 



X. Comlmalion of the Electric Column, the Thermometer, 

 Barometer, and Hygrometer in one Instrument, for Electro- 

 atmospherical Researches. By A Coruespoxdent. 



To Mr. Tilloch. 



Sir, — The electric column of De Luc promises to be not only 

 an interesting but also a useful apparatus, as its powers seem to 

 be influenced by the electrical state of the atmosphere. It has 

 occurred to me, that a combination which would at one view give 

 all the different states of the atmosphere, would be very con- 

 venient in electro-atmospherical researches. If you should con- 

 sider the following worthy a place among your more important 

 communications, it is much at your service. 



Yours, &c. 



D, 

 I trust the plan will not require much explanation. It may he 

 sufficient to say that A (Plate I. fig. 6) is a powerful column insu- 

 lated on Mr. Singer's plan; C, a thermometer; and B, a barometer, 

 which should liHve a brass or an ivory index with a gilt wire to 

 form a communication with the bottom of ihe column ; the 

 parts EF mav be covered with sealing-wax; G may be a small 

 figure or a glass tube ; D is the index of a catgut hygrometer 

 stretched on small pulleys on the bottom of the stand, as is re- 

 presented by H — I (fig. 7 and 8.) 



XI. Mr. Farey's Correction of his Remarks in our last Num- 

 ber, regarding a Geologist being attached to tht Government 

 Trigonometrical Establishment. 



To Mr. Tilloch. 



Sir, — Evident justice to the Parties who direct the Govern- 

 ment Trigonometrical Survey of our Island, carrying on under 

 the Board of Ordnance, and toward a highly respectal)le and 

 able Mineralogist and Geological Investigator (the President tins 

 year of the Geological Society) requires of me, without delay, to 

 "' D 4 apologize 



