676 Journal of Agriculture, Victoria. [11 I^ov., 1918. 



egg-beater be now immersed in the water it will be found on rotating 

 the handle that tbe lime and casein are entirely sucked into the water 

 with which they are immediately incorporated. The casein dissolves, 

 or rather forms an emulsion, after a while, but the greater part of the 

 lime merely remains in suspension. 



(2) Incorporate the casein Avith the aid of an egg-beater, as pre- 

 viously described, in a 10 per cent, solution of soda carbonate at the 

 rate of 10 lbs. to 4 gallons. Some confusion exists in connexion mth 

 the term carbonate of soda, which is really the correct term for washing 

 soda, and not for baking soda, although the latter is sometimes sold in 

 grocers' shops under the name of carbonate. The correct term for bak- 

 ing soda is bicarbonate of soda. 



The casein solution should be made up a day or two before use, and 

 well stirred before each withdrawal. If prepared by the second method 

 there may be a slight tendency to scorching of the foliage owing to 

 the presence of small quantities of carbonate of copper in the resulting 

 Bordeaux; on the other hand, it will tend to render this slightly more 

 active, inunediately after application, by increasing the immediatelv 

 available soluble copper. 



Choice of Lime. 



With the lime packed in air tight tins, previously referred to, no trouble 

 will be experienced, but with the lime usually obtainable from country 

 stores attention to certain points is necessary. The fresher the lime — 

 in other words, the more recently it has been burnt — the better. Fresh 

 lump or " roach " lime should only be used ; it should be quite free from 

 powder. Lime deteriorates rapidly on keeping, as was explained in last 

 issue (pp. 594) becoming first slaked and subsequently carbonated under 

 the action of water vapour and carbonic acid present in the air.* 

 If merely slaked little harm will result, it will only be necessary to use 

 somewhat more of it. The action of carbonic acid, however, is far more 

 undesirable. Carbonate of lime is of little use for neutralizing copper 

 sulphate, but the chief objection to lime which has become carbonated 

 is the presence of much copper carbonate in the resulting " Bordeaux," 

 and the scorching of the foliage which frequently results therefrom. 

 Unfortunately both changes occur simultaneously, so that lime which has 

 been stored for a while invariably contains more or less of the undesir- 

 able carbonate. Analyses of lime kept in store hare shown that even 

 after two months' storage it may only contain 70 per cent, of pure lime, 

 whilst after eight months' storage the lime content may have fallen so 

 low as 48 per cent.f 



Slaking of Lime and its Subsequent Preservation. 



The importance of the proper slaking of lime is well known to 

 bricklayers and plasterers ; vine growers are less familiar with the sub- 

 ject, though it is of equal importance in connexion with the making of 

 Bordeaux mixture. If the lime milk be properly prepared less trouble 

 will be experienced in the way of spray nozzles clogging. It is in fact 

 largely owing to greater freedom from nozzle trouble that copper soda 

 owes its popularity. 



* 100 lbs. of pure quicklime, after being slaked would weigh 135 lbs. ; when completely carbonated 

 its weight will have increased to 178 '6 lbs. 

 t Millardet and Gayon, 1888. 



