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of Cereals because the Purity of 6ereals does not have to be declared. The method of 

 making- Purity tests does not differ materially from that adopted in other Stations, but 

 there is one important exception. At present and until 1st August when the Seeds Act 

 comes into force, Purity tests on Grasses are made on what we call the Irish Method. 

 Light seeds are called pure seeds or in the words of the Testing of Seeds Order, a Grass 

 seed shall be considered to be pure "if it consists at least of the two united pales, 

 regardless of the state of deveilopment or even the . entire absence of the 

 caryopsis or kernel within the pales" This is contrary to all Continental practice, 

 though this method is adopted in some of the British colonies. I am aware that Con- 

 tinental analysts despise this method and my friend. Professor Voigt, described it to me 

 last year as a method only fit for use by chemists! It may, therefore, be of interest to 

 coiisider the reasons for adopting this method. When the Irish Station was started twenty 

 years ago, the technical advisors of the Department were confronted with the problem of 

 the occurrence of large quantities of Ryegrass seed containing much of this light seed. It 

 appeared that the best way to encourage the cleaners to remove this would be to penalise 

 it by bringing the light seeds into the Germination test where their inability to grow 

 ' would reduce the percentage of Germination by a greater amount than their inclusion in 

 the Impurities would reduce the Purity of the sample. It is unnecessary perhaps to 

 elaborate this argument to an audience like this, but I will take, to show what I mean, 

 an extreme case of a sample of Ryegrass, containing by number 50% good plump germi- 

 nating seeds and 50 % light seeds. This sample would show by an Irish test 100 "/o purity 

 and 50 °;'o germination, by a Continental test 75 % to 80 °/o purity and 100 % germination. 

 The Irish method gives the lower figures and more particularly shows a low germination 

 for the sample. Since the farmer as a rule pays more attention to germination figures 

 than to purity figures it is obvious that the cleaner will be encouraged to blow out the 

 light seed. The adoption of this method proved very satisfactory in Ir-eland, and when 

 the Scottish Station was opened they adopted the same method. The English Station was 

 started in 1917, and though the Seed Trade asked for the adoption of the Continental 

 method, it was thought inadvisable to have two methods in use in the same country. 

 The Irish method was, therefore, adopted, and the matter left for reconsideration when 

 the Seeds Act came into force. In framing the Regulations under the Seeds Act this 

 wish of the Trade for the Continental method has been granted and after 1st August next 

 we shall adopt, in England and Scotland at least, the Continental method of Grass Seed 

 Testing. The reason stated by the Seed Trade for desiring the latter method is that 

 the Irish method interferes with their Continental Trade. I sometimes wonder how far 

 this is the real reason. Personally I hold no brief for either method. The Irish method 

 as practised by us is illogical since we treat a Grass seed without any caryopsis and 

 which, therefore, cannot grow as a pure seed, and at the same time we call broken 

 Clover seeds or empty Mangel clusters impurities. On the other hand I really believe 

 the adoption of a universal method for all seeds based on the Irish method of grass 

 testing would result in improved seed. You may argue that the Irish method leads to 

 absurdities in extreme cases, but so does the Continental method. I will not discuss the 

 pros and cons of the two methods any further, since the matter will probably be brought 

 up again before the end of this Conference. 



I do not think that our methods of making Purity tests differ in other respects from 

 those in common use elsewhere. I might perhaps mention that for Dodder examinations 

 we use a home made machine ^with an endless velyet band which passes the whole of the 

 sample before the eye of the analyst. Also I would like to draw the attention to those 

 who do not use them to the torsion -balances made by the Torsion Balance Company of 

 New York. I find that in weighing small unknown quantities of impurities three to five 

 weighings can be made on this balance, while one weighing is being made on an 

 ordinary chemical balance. 



I might add that at present no field trials are being conducted by the English 



