Sulphate of ammonia has no doubt a more lasting quality, but its application in continuance is of doubtful utility, owing to the fact that although the ammonia is nitrified and taken up by the plant life, it still remains. The acid is in the soil and gradually becomes a poison.

Too little value has been placed by the chemists of the present day on the attraction of nitrogen by leguminous plants or by the proper rotation of crops. They would seem to look upon the matter more from the merchants' point of view than from the agriculturists.

Worthless manures are sold year by year to farmers, simply on a guarantee of purity, and the millions of pounds expended, as set forth by Professor Somerville, cannot be taken as representing the return to the farmer, but on the other hand there is in most instances a loss both to the farmer's pocket and to the fertility of the soil.

Chemists are too apt to assume that the farmer knows the chemistry of his soil and of plant life; but the majority are entirely ignorant of both subjects, and depend upon artificial manure as their mainstay, simply on the merchants' assurance of its efficacy.

I could point to many men who look to nitrate of soda as a help to nitrify the various constituents in the soil, without in the least knowing what those constituents are, and with entire ignorance of plant life or its requirements.

Professor Hellriegel has recently carried out some very interesting experiments in breeding the bacteria of nitrogen from the nodules formed on the roots of leguminous plants and has brought out what is termed "nitragin." I have made several experiments with this, but have only found it to answer upon poor soil badly farmed. Upon such soils, with potash and phospates,

the result was most satisfactory, while to well-farmed land the benefit was almost nil.

I think that too much stress cannot be laid upon the more liberal use of potash and phosphates, especially basic slag, but, in the case of slag, care must be taken in seeing that it is finely ground.

There can be no doubt that, in the past, very large sums of money have been thrown away by farmers in purchasing and applying worthless manures, while large fortunes have been made by the merchants.

I hold that it would be well, in the interests of agriculture, that there should be more practical demonstrations, and that qualified persons should be appointed in small districts to give advice to the farmer as well as to the agricultural labourer.

Agricultural colleges will no doubt benefit the next generation; but what is to be done in the meantime ? ASTLEY VIGERS, Fellow.

(B.)

The able and useful Paper on "Artificial Manures," read on December 9th, 1901, necessarily-owing to time limits-mentions only a few, the most important and the most extensively used, of the artificial manures. The author's object was "to attempt to indicate some of the

considerations that should be duly weighed by those "who have to use artificial manures." The author has compared the two most important nitrogenous manures, also the two most important phosphatic manures, besides giving valuable hints and information on the use of potassic manures and on a few other matters. Whilst agreeing with the general conclusions drawn, if one may criticise the Paper, it seems that Dr. Somerville has hardly laid

sufficient emphasis on the importance of taking into consideration the nature of the soil-both its chemical and physical composition-when deciding which artificial manure is more likely to produce the best economical effect.

In comparing the effects of nitrate of soda with those of sulphate of ammonia, this is to a certain extent pointed out, by showing that the use of ammonium salts removes limes from the soil and so is not to be recommended for use on soils poor in lime. But another consideration is that on soils very rich in carbonate of lime, there may, under certain climatic conditions, be loss of ammonia by volatilization. Also there are a few soils whose physical condition seems to be injured by nitrate of soda.

The evidence that nitrogen is lost during the conversion of ammonium salts into nitrates in the soil, is not very strong. Ammonium salts are better than nitrates, on many soils, for turnips and swedes; this is true also as regards potatoes. With regard to the influence of these manures on the quality of the crops, even with barley it is only when the supply of nitrogen is too liberal that it has any material influence on the quality, and the influence on the quality of a root crop is likely to be more marked than on that of any cereal crop.

When ammonium salts are used, it is even more important than with nitrate that the supply of cinereals, phosphates, potash and lime, be adequate. In considering the relative merits of superphosphate and basic slag, the nature of the soil is of the greatest importance; there are some soils on which one would always expect slag to give the better results, and others on which superphosphate might reasonably be expected always to be superior. Another possible advantage of superphosphate in some seasons, is its quicker stimulating effect on the

young turnip or swede plant, thus helping it past the attacks of "fly."

Regarding the use of potassium salts on potatoes, some experiments seem to show that the use of chlorides in any quantity tends to reduce the amount of the starch harvest even if not the total weight of the crop. EDWARD KINCH, Associate.

On Mr. J. H. Hanson's Paper on "Rivers
Pollution."

(Transactions, Vol. XXXIV., PP: 135-153.)

(A.)

I have read Mr. Hanson's interesting Paper carefully. The title of the Paper is general, but it refers almost entirely to the Yorkshire rivers. However, for all that, I think that in discussing such a Paper the Members of The Institution should not forget that in any legislation for the purification of these waters the millers are undoubtedly entitled to consideration on account of the established trades, and that quite a different law is required for the protection of owners of property on such rivers from what would be required on the rivers in this neighbourhood, which have a value of some thousands a year as letting for rod fisheries. On the Usk we have tributaries near Newport, Monmouthshire, on which have been started galvanising and other works that seriously pollute the river for fishing purposes. In such a case it is clear that under no circumstances should owners of mills or works be allowed to pollute a river, but should be compelled to make filter beds and tanks, whatever might be the cost.

S. H. COWPER COLES, Fellow.

(B.)

Mr. Hanson's Paper on the above subject, written from a millowner's point of view, is a very valuable contribution to a very important subject.

The prevention of pollution of rivers is of material importance, and should not, it is thought, be looked at from an individual or class point of view. It is but reasonable, on the other hand, that if injustice is done to a particular class by the want of or by ineffective legislation, every effort should be made to amend the law.

Millowners in the past, obtaining very large powers over the water of running streams, proceeded to pollute those waters, thereby injuring those below them and eventually rendering the water dangerous to their neighbours and less effective for their own use.

On the other hand it may be said that the riparian owners and occupiers took no efficient steps to stop pollution, but practically gave away their birthright to a continuance of the stream in its normal condition of purity.

If the fault lay with the millowner it is for him to repair it, but if the riparian owners and occupiers contributed to the damage, they should likewise contribute to the cost.

The fact seems to be that, without some special enactment, the riparian owners were and are helpless; that the millowner did what seemed to him good in his own eyes, to the injury, not only of his riparian neighbour, but also of the millowner below him.

Even at the present time the law as to the prevention of pollution is largely inoperative, except where special Acts have been obtained, and even in these cases the efficiency is, to say the least of it, doubtful.

It appears to be desirable that the law with regard

F