On the Theory of Comhustion. 81 



Brought over £. 85,630 

 2u 1 ear. Roads and bridges - - - 20,000 

 Aberdeen ----- 3,300 



Cromarty ----- 2,500 



Caledonian canal - - - 50,000 

 Wick - ----- 2,000 



Carlisle to Port Patrick - 5,630 



85,630 



3d Year. Roads and bridges - - - 20,000 



Aberdeen - - - . . 5,300 

 Caledonian canal - -. - 50,000 

 Wick ----_. 2,000 

 Carlisle to Port Patrick •=• 5,650 



' 83,150 



4th Year. Roads and bridges - ^ - 1 2,000 

 Aberdeen - _ - _ _ 5,500 

 Caledonian canal - - - 50,000 



- ' 67,500 



5th Year. Roads and bridges - - - 12,000 

 Aberdeen ----- 5,300 

 Caledonian canal - - - 50,000 



67,300 



6th Year. Roads and bridges - - - 12,000 



Caledonian canal - - - 50,000 



62,000 



7th Year. Caledonian canal - - - 50,000 30,000 



© 



;^. 501,450 



London, _^___ 



March 15, ,S03. ThOMAS TeLFORD. 



[To be concluded in our next.] 



XIII. On the Theory of Combustion. 

 To the Editor of tlie Philosophical Magazine. 



A SIR, Edinburgh, May 20, 1803. 



s you have admitted Mri Henry's claim in favour of 

 his father's discover)', I trust you will do equal justice to 

 an author, in whose cause I prtrstime, though unauthorized, 

 t') appear. In your la-^t number is a communication from 

 Mr. Portal on the subject of combustion : he there men- 

 lions the opinion, that heat and light are different bodies, 

 simultaneously separated in thiu process, without their hav- 

 Vot.XVI. N0.61. F ing 



