ivnn i, tiif.i 



source of manure ; and, further, this op'nion has been 

 borne < ut by actual field experiments. If, tKerefore, 

 soot is to be preferred in certain localities, it must 

 be on account of properties other than tho^e of a 

 manure pure and simple. From a number of aualyses 

 it will be sufficient to select the two following ones 

 as fairly representative of average good commercial 

 Boot, which are placed by the side of a very poor 

 sample for better comparison. 



Good soot. Bad. 



No. 1. 



4-90 .. 

 33-01 .. 



No. 2. No. 3. 



Water 490 237 2-40 



^Carbonaceous matters ... 33*01 49'01 4186 



Tar and hydrocarbons ... 27-42 15-83 -30 



. ( Chloride of ammonium 5-69 7'49 trace 



' jt Sulphate of ammonia 4-09 -81 -89 



Oxides of iron and alumina 7'4S 7-70 14-16 



Sulphate of lime 4-49 2-72 5-36 



Sulphate of Magnesia -50 "86 'IS 



Siliceous matters 12-41 13-21 34-85 



lOO'OO 



100-00 



10000 



*Containing nitrogen (in- 

 soluble form) 1-66 1-24 1-25 



Equal to ammonia 2-03 1-50 1-51 



fC ntaining available 



ammonia 2'85 



2-59 



Total ammonia... 4-8S 400 1-74 



Matters insoluble in water 74-dO 82-20 91-75 



Matters insoluble in spirit 57-90 73-70 96-90 



From the above results it will be seen that good 

 soot should contain at least 4 per cent of ammonia, 

 and not more than 20 to 21 per cent of mineral 

 impurities, such as sand, oxides of iron, and alumina. 

 No. 3 shows us the composition of a very inferior 

 quality, there being nearly half its weight of mineral 

 matters, while the total ammonia is not more than 

 1-74 percent. It is important also to notice that of 

 this 1-74 there is only -23 present in the form ef avail- 

 able ammonia, as compared with 2-85 in No. 1, and 

 2-59 in No. 2, samples. This comparison leads further 

 to the observation that even in No. 1, the be.st sample, 

 there is onlj' 2-85 of the ammonia present in a form 

 available as plant food, the remainder 203 existing 

 in a condition insoluble in water, and probably of very 

 little practical use to the growing crop. 



Indeed, a glance at the above analytical results 

 will at once show that, so far as a source of ferti- 

 lisiug matter is concerned, it is only the available 

 ammonia that is of any manuria! value in the soot. 

 This ammonia is in fact, present in the form of an 

 aiumoniacal salt, sometimes in union with chlorine, 

 and sometimes — perhaps more frequentlj' — in combi- 

 nation with sulphuric acid, which latter is produced 

 from the sulphur present in the original coal. 



It will be further noticed what a large proportion 

 of the three samples is i-asoluble in cold water ; 

 thus, in No. 3 there is nearly 92 per cent., in No. 

 2 as much as 82, and in No. 1 there is still 74 out 

 of 100 that is of no use as a soluble manure. 



It is therefore worth while, in these days of agri- 

 cultural depression to ascertain whether it is possible 

 that good soot will be an economical source of soluble 

 nitrogen as compared with nitrate of scda, For this 

 purpose we will assume that commercial soot of good 

 quality, representing the mean analysis of Nos, 1 and 

 2, can be obtained at 6d. per bushel weighing 28 lb, 

 Also, that good nitrate of soda, testing 95 per cent 

 purity, can be obtained at 12s per cwt, 



Nitiate of soda compared with ordinary soot. 



Nitrate of soda. Soot, 



Ijcwt, 36 bushels, 



Quantity of manure per acre 1681b. —1008 lb, 



Cost of manure..... 18s. 18s, 



Soluble nitrogen 26 2/5 lb. 22 3/5 lb. 



Equal to ammonia 321b. 27A lb. 



From these figures it will be seen that, with the 

 it(p«&ditur& of tbe sinaQ mon^y/ the nitr&te gives 



nearly 5 lb. more of available ammonia, and that, in 

 order to make the quantities equal, it woulr' he 

 necessary to apply 42 bushels of soot, costing 21s., as 

 against 18s. for the nitrate of soda. 



In other words, the latter would appear to be quite 

 16 per cent cheaper than soot at 6d. per bushel, aud 

 that unless the price is i^d., the farmer had far 

 better use nitrate of soda as a top dressing for his 

 wheat. Moreover, in these calculations only the original 

 cost of the manures has been considered ; but if we 

 compared the extra cost for carriage and distribution 

 caused by the increased bulk of the soot, the differ- 

 ence in the expense would be still greater. Thus, 

 42 bushels of soot at 281b. each, would represent 10^ 

 cwt. as against I5 cwt. nitrate of soda. 



Let us next ascertain how far these chemical cal- 

 culations have been borne out by actual field experi- 

 ments, and we cannot do better than refer to a most 

 exhaustive paper, " On Experiments with Different 

 Top Dressing.s upon AYheat," by the late Dr. Voelcker, 

 which was published in the Journal of the Royal 

 Agricultural Society in 1862. 



The experiments, which were carried out on the 

 College farm at Cirencester, include a number of 

 different kinds of manure ; but for our immediate pur- 

 pose it will only be necessary to refer to those we are 

 now comparing, namelj : a dressing of 1^ cwt. ni- 

 trate of soda gave an increase over the unmanured 

 plot of 10,', bushels of corn and 10^ cwt. of straw, 

 while 32 bushels of soot gave only an increase of 7f 

 bushels of corn and 6| cwt. of straw, the nitrate 

 thus giving an increase of nearly 25 per cent more 

 corn and 35 per cent more straw than the soot. Both 

 manures were carefully analysed, and found to be of 

 good quality. 



These results, therefore, fully confirm the previous 

 calculations respecting the agricultural value of the 

 two dressings, and it seems therefore desirable, at 

 present market prices, to confine the use of soot to 

 those districts where it can be obtained for about 4Jd. 

 per bushel, and also to certain cold damp clays, 

 specially liable to produce mildew, but upon which soot 

 seems to exercise its popular property of averting this 

 disease. Indeed, if we refer to the analysis of No. 1 

 sample it will be seen what a much larger proportion 

 of tar and hydrocarbons there is, as compared with 

 No, 2 sample, there being 27-42 in one case, aud 

 only 15-83 per cent in the other; while in No. 3 

 there is only a mere trace. 



It is therefore important to have as much of these 

 compounds in the soot as possible; and the extent to 

 which a sample is soluble in spirits of wine will be a 

 useful indication of its quality as a preventive of fun- 

 goid disease, as well as against the attacks of insects. 



lu regard to this latter point there can be no doubt 

 that it must be most effective, acting both mechanically 

 and chemically. Further when applied in large quanti- 

 ties, such as forty bushels per acre, soot must supply 

 a warm covering and protection from cold wind to the 

 yotmg plants, aud its dark colour favours the increased 

 absorption of the sun'a heat rays. 



In conclusion, it may bo repeated that as a simple 

 manurial top-dressiug soot cannot be economically com" 

 pared with nitrate of soda, except in those districts 

 where it can be purchased at 4^d= per bushel; but 

 as a useful preventive against fungoid and ii'sect at- 

 tacks it is likely to be etill employed with marked 

 advantage, even when the price is as much as fld, 

 per bushel, provided it is of really good quality.— 

 John Hughes, F.CS,, Consulting Chemist to the 

 Planters' Association of Oeylon. 79, Mark-lane, E,0.— 



Field. 



♦ — — 



AGBICi'LTtEli ON TKE CONTlKlilNT OV 

 EUKOPE. 



{Spccic'I Letter.) 



pAltlB, April l(5j 

 An experienced authority asserts that he has irl' 

 creased by five per cent the yield of milk from his 

 cows, and which his ueighbour.s admit, by attend- 

 ing to the following simple rules ;— Never worry the 



co>v3 Oil tlieiE goiflg or returning between tbij field 



