VOL, LXXX.] PHILOSOPHICAL TRANSACTIONS. O49 



must have entered the blood; which is 3 times as much as that which did not 

 enter, but was employed in forming the fixed air in the lungs. 



He breathed in 100 oz. m. of dephlogisticated air, of the standard of 1.0, till 

 it was reduced to 58 oz. m., and by washing in water to 52 oz. m. of the standard 

 of 1.75, with 2 equal quantities of nitrous air. The computations being made 

 as before, it will appear, that before this process, this air contained 66 oz. m. of 

 phlogisticated, and 34 oz. ni. of dephlogisticated air; and that after the process 

 there were 30.368 oz. m. of phlogisticated air, and 21.632 oz. m. of dephlogis- 

 ticated air. In this case therefore, the dephlogisticated air that disappeared was 

 13.3 oz. m. weighing 7-8 gr. and the fixed air was 6 oz. m. weighing 4.4 gr.; so 

 that here also about 3 times as much entered the blood as did not. These expe- 

 riments he repeated many times, and though not with the same, yet always with 

 similar, results, the greatest part of the dephlogisticated air, but never the whole, 

 passing the membrane of the lungs, and entering the blood. 



When the results above-mentioned are compared, it will appear, though the 

 observation escaped Dr. Goodwyn, that part of the phlogisticated air entered the 

 blood, as well as the dephlogisticated air; or, which is the same thing, that the 

 dephlogisticated air which was consumed was not of the purest kind. This expe- 

 riment Dr. P. repeated so often, and always with the same result, that he is con- 

 fident he cannot be mistaken in this conclusion. This fact, of which he had 

 no previous expectation, he first thought might be accounted for by supposing 

 that the 2 constituent parts of atmospherical air, viz. the phlogisticated and de- 

 phlogisticated air, are not so loosely mixed as has been imagined; but rather that 

 they have some principle of union, so that, though they may be completely sepa- 

 rated by some chemical processes, they are not entirely so in this; but that the 

 dephlogisticated air, passing the membrane of the lungs, carries along with it 

 some part of the phlogisticated with which it was previously combined. But, at 

 the suggestion of Dr. Blagden, he now thinks it more probable, that the defici- 

 ency of phlogisticated air was owing to the greater proportion of it in the lungs 

 after the process, than before. 



JClI. An Account of the Trigonometrical Operation, by which the Distance 

 between the Meridians oj the Royal Observatories of Greenwich and Paris has 

 been determined^ By Major-general IVm. Roy, F. R. S., and A.S. p. 111. 

 The trigonometrical operation which is the subject of the present paper, had 

 its commencement in the measurement of a base on Hounslow-heath in 1784, 

 an account of which was given to the r. s. in the following year. On the com- 

 pletion of that first part of the business, it was little expected, that nearly 3 full 

 years would have elapsed before an instrument could be obtained from Mr. 

 Ramsden for taking the angles! At length however the instrument was pro- 



VOL. XVI. 4 O 



