Studdert — 0)1 Free and A/btonuioid Anunonia. 459 



XLI. — An Estimation of the Free axd ALBUMEsroiD Ahmonia 



YIELDED BY THE STAGNANT WaTEES OF THE DuBLIN StEEETS, 

 AS COirPAEED "WITH THE QUANTITIES OF THOSE SuBSTANCES OB- 

 TAINED FEOil THE LiFFEY AVaTEE, AFTEE EECEIYING THE SeWAGE. 



By Lancelot SiroDEET, LL.D.. Ex-S.T.C.D. 



[Eead lOth Januaiy, 1876.] 



DuEiNG the Session of 1874-5 of the Eoyal College of Science, 

 Stephen's- green, several examinations were made there of Dublin well- 

 waters ; and also some determinations like those that follow for the river 

 water. As a sequel to those analyses, the suggestion of the Professor 

 of Chemistry in that college, j\Ir. Galloway, induced me to undertake a 

 series of estimations of the ammonia yielded by the surface-water of 

 some streets and squares in Dublin, taking as the standard of compa- 

 rison the water of the Lrffey, near where the sewage is discharged into 

 the river. 



The results of my examination, conducted during jS^ovember and 

 Decembe r last, in the College of Science Laboratory, are now laid 

 before the Royal Irish Academy. 



Altogether twenty-nine of these street waters were examined : the 

 samples dealt with were collected, in my presence, at the times and 

 places stated in the Table appended to this paper : the mud, also, left 

 from some of these pools, was examined for ammonia, which reached 

 two parts in the hundred, calculated after allowing for moisture ex- 

 pelled at 212° Fahrenheit. The river water was collected at inter- 

 vals during the two months, from four different places, namely, at 

 Eden-quay, Aston's-quay, Burgh-quay, and Sir John Rogerson's-quay, 

 four hours after high water at Dublin bar. 



The method employed for determining the quantity of ammonia 

 yielded by these waters and muds is that devised by Messrs. Wanklyn 

 and Chapman. This process is almost universally allowed to be the 

 best yet made known for ascertaining the character of the nitrogenous 

 matter in waters ; its quantitative results are accurate, and they are 

 obtained with rapidity. It may be well to state, for the information 

 of any unacquainted with the Wanklyn and Chapman process, that 

 under the term ^^ free ammonia,^^ these chemists include ammonia not 

 only present as such, or in combination with acids, but also the ammonia 

 that, after adding a saturated soda carbonate solution, is evolved by 

 distillation from ui'ea, or other easily decomposable nitrogenous organic 

 bodies. The term free ammonia is therefore not strictly correct ; but, 

 taking it in this special sense, it would be difficult to substitute any 

 other term more convenient, or less open to objection. 



The Table of results gives the figures for the Lilfey standard at the 

 head of the list. The quantities of the free and the albuminoid 

 ammonia obtained from the several street and Litfey waters are calcu- 

 lated as grains in the gallon, and also as milligrammes in the litre 

 of each water, respectively, examined. 



■. R. I. A. PROC, SKK. II., VOL. TI., gCIE.NCE. o C 



