688 EXPERIMENT STATION RECOKD. 



" Purifying by irrigation can not equal this method in completeness. Clarify- 

 ing with limewater is insufficient and such a preliminary purifying in no wise 

 increases the efficacy of biological action. Equally insufficient is the purifica- 

 tion of waste water by means of colloidal clay and limewater, and a preliminary 

 treatment with these substances is useless. These methods are scarcely as 

 good as the lime-purifying process, and have the disadvantage of not leaving 

 the water clear. Colloidal clay must therefoi-e be omitted from the substances 

 that can be used for the purification or clarification of waste water. 



"A considerable clarifying effect must, however, be attributed to ferric sul- 

 phate, and its use should be especially efficacious in the case of waste dairy 

 water, for this contains its albuminous matter in a colloidal condition. In the 

 experiments, 65 per cent of the total albumin was decomposed. Used in the 

 preliminary treatment, ferric sulphate increases very considerably the biological 

 purification. The use of this compound is therefore to be reconnueuded where 

 bacterial action alone proves to be insufficient." 



The agricultural value of the sludge is considered questionable. 



A summary of the experience gained in the treatment of the wastes from 

 the scouring of wool, M. K. Crohitist and A. D. Weston {Eupiu. ami Con- 

 tract., 44 (1915), No. 19. pp. 370-376). — Analyses of wool scouring liquors sho\T 

 that they are a concentrated brownish liquor containing large quantities of or- 

 ganic matter in solution and suspension, soap and alkali, and waste containing 

 potash and grease. 



It was found by experiment that ordinary sewage treatment methods could 

 not be applied effectively from the standpoint of purification, or economically 

 from the standpoint of recovery of the grease and potash. Experiments with 

 a number of .special methods are doscribeil. and it is concluded that " the best 

 method seems to be the separation of the concentrated liquor, the recovery of 

 lK)th potash and grease or the grease alone, and the purification of the dilute 

 liquors together with the remafuing liquors, after the recovery process by sew- 

 age purification methods. . . . 



" By the Smith-Leach process the wool scouring liquor can be entirely de- 

 stroyed, the resulting products being grease, potash, distille<l water, .sand, and 

 mud. No liquid remains to be treated by sewage metho<ls. From such data as 

 are available this method of disposal will yield a fair return upon tlie cost of 

 the plant and cost of operation, and there remains no liquid of a polluting na- 

 ture to cause nuisance." 



RURAL ECONOMICS. 



Safe farming. B. Knapp (T. S^. Dcpt. A (jr.. Office Sec. Circ. 56 (1916), pp. 

 16). — The author in this address, delivered before the second annual conference 

 of Cotton States Bankers, defines safe farming as living from the prtxlucts of 

 the farm and from the sale or exchange of the sundry products other than the 

 main money crop, and then the production of money crops for the market. He 

 recommends that this organization undertake the following work : 



Conduct a campaign of education of merchants and bankers to get the basis 

 of credit changed to the new safe farming basis. Secure, if possible, the adop- 

 tion of some sort of rate sheet or schedule for farm loans, which discloses the 

 plan of farm operation. Take up in every county and market town the estab- 

 lishing of some system by which the farmers may be able to market, at fair 

 prices, every product of the farm, with arrangements for assembling, standard- 

 izing, packing, handling, and shipping in case the local community is oversup- 

 plied. Work with the agricultural forces of each State in planning and assist- 



