Reclaiinincc Hloiintam Land 



449 



natural grasses springing up spontaneously 

 wiierever the land had been drained and 

 limed. They are, therefore, of the opinion 

 that a great portion of the mountain land in 

 this district might be successfully and perma- 

 nently reclaimed by judicious draining and 



liming, with every prospect of a fair return 

 for the outlay, The judges saw no land that 

 had been reclaimed by ploughing, liming, 

 cropping, and sowing do^vn, forming good 

 pasture ; the artificial grasses were rapidly 

 displaced by daisies and mosses. 



A NE W SE WA GE EXPERIMENT. 



ANOTHER scheme for the purification 

 of our sewage has been added to 

 those already brought under the notice of 

 agriculturists. The new experiment is known 

 as " Dougall Campbell's patent." A short 

 time ago a practical experiment was made at 

 the Government works at Tottenham, in the 

 IDresence of several gentlemen interested in 

 the inquiry, including Mr Alfred Sibson, 

 F.C.S., who, as analytical chemist, attended 

 to investigate the process and the results 

 obtained ; and his report has just been 

 issued. The arrangements of receiving and 

 settling tanks, &c., were the same as are in 

 ordinary use at these works, the continuous 

 system being adopted ; and although the 

 subsiding tank is well constructed, so as to 

 allow of the effluent water passing off with 

 as little disturbance to the sediment as 

 ])0ssible, tlie size of the tank is hardly suffi- 

 cient to secure a maximuvi clarifying effect 

 from any process that might be employed. 

 Tanks of large dimensions are being con- 

 structed which will render the appliances 

 more complete in this respect. Of course, 

 this incapacity of the subsiding tank was 

 very unfavourable to the experiment. Then 

 again, other arrangements are of such a 

 primitive kind that the precipitating mixture 

 had to be added to the sewage by a man 

 bailing it out of a trough with a tin sauce- 

 pan \ and, there being no sheds available, 

 the precipitated matter had to be dried in the 

 open air, at a time when thunderstorms and 

 rain occurred almost every day, so that not 

 only were many days lost before the yield 

 from the experiment could be got tolerably 



VOL. IX. 



dry, but the continuous wetting must have 

 washed out some of the ammonia which the 

 mass contained. 



The process essentially consists in adding 

 to the sewage as it enters the works phosphate 

 of lime in a soluble state, the materials 

 employed being bone-ash and sulphuric acid ; 

 and after sufficient admixture, precipitation is 

 accomplished by adding lime, which, being 

 one of the best precipitants for sewage as re- 

 gards purification of the water, is in ordinary 

 use at Tottenham. " In a sanitary point of 

 view," says Mr Sibson, " this process appears 

 to be all that could be desired, the removal 

 of all offensive water from the sewage water 

 being complete and rapid. No objectionable 

 smell was perceptible from the sewage under- 

 going the operation ; while the effluent water 

 was satisfactorily clear, and fit, in my opinion, 

 to be discharged into any river without in- 

 jury, although not so entirely free from sus- 

 pended matter as it could undoubtedly be 

 rendered by the use of larger tanks, such as 

 are now being constructed, and the necessity 

 for which has doubtless been apparent in all 

 the processes that have been tried at these 

 works." Now as to the product obtained. 

 The "precipitated phosphate of lime," being 

 in a condition in which it can be readily as- 

 similated by plants, is but little inferior to 

 " soluble phosphate " as a manure. In analysis 

 it was estimated by a process devised by Mr 

 Sibson, and commonly used by him for de- 

 termining this constituent of phosphatic 

 manures, in which it frequently occurs, con- 

 stituting an item of considerable importance, 

 although sometimes overlooked by analysts. 



F K 



