]0 Feb.. jgi2.] Vine Diseases i)i France. 119 



The solutions or semi-solutions are very fluid, and never clog sprav 

 nozzles. 



Being richer in metallic copper* than sulphate, considerably less is 

 required. In other words, \erdet may be looked upon as being twice 

 as strong as sulphate, so that i Ih. to 10 gals, of water (i per cent.) 

 would be equivalent to a Bordeaux mixture containing 2 lbs. to 10 gals. 

 Preparation is almost instantaneous and very simple; it is only necessary 

 to thoroughly mix with a small quantity of water for a few moments, and 

 then to dilute to the required bulk. 



As ^•erdet does not lea\e such \-isible marks on the sprayed plants as 

 copper-lime or copper-soda, supervision of the work done is more diffi- 

 cult. This slight defect is easily corrected by the addition of plaster 

 of Paris at the rate of h lb. to 10 gals, of .spray mixture. 



POTATO DIGGING MACHINES. 



G. Scyiimiir, Potato Expert. 



The harvesting of the potato crop by hand has always proved a tedious 

 and expensive operation. Especiallv so has this been the case in late 

 years, owing to the scarcity of labour, and the indifferent manner in which 

 the work is carried out by those available. Rates for this w-ork have 

 increased during the last 20 years bv 50 per cent, to 75 per cent. This 

 increase, coupled with the fact that the delay has frequently caused the 

 har\-esting to be prolonged into the wet season, and thereby injuring the 

 condition of the soil for the succeeding cereal crop, especially barley, has 

 created a want for a satisfactory potato-raising machine The following 

 points, .some of which have hitherto proved insurmountable, are required 

 in a satisfactorv digger : — 



1. That it shall lift the crop clean from the soil and not cover those lifted. 



2. That it shall leave them in convenient rows for ])icking u\>. 



3. That it shall not bruise or damage the tubers. 



4. That it shall leave the land in a level and workable condition. 



Inventors have followed two well-defined lines in their efforts to solve 

 the.se problems. One is the separation of the tubers from the soil, 

 generallv by scattering them to one side of the machine; the other, by 

 raising the soil and tubc^rs as with a scoop or shovel and passing the 

 whole on to an endless band or elevator provided with spaces for the soil 

 to pass through, the tubers being deposited in a neat row at the rear of 

 the machine. The soil is returned to its place again, leaving the 

 field quite level. 



The history of potato- raising machinery is one of manv failures and 

 some partial successes. Probably the most primitive attempt was die 

 potato plough made by Howard and others more than 40 years ago. This 

 was as simple as it was possible to make it, being neither more nor less 



* Neutral acetate contains 31-7 per cent, of copper. Verdet .ijris, which is a mixture of bi-, sesqui-, and 

 tri-basic acetato varie<? somewhat accordins; to the preponderance of one or other of these salts ; if pure, its 

 copper stren^nh varies between 34 and 35 per cent. The coiMuercial form contains abcut 33 per cent. 

 (Dejeanne). 



