378 .loUKNAL OF THE DEPARTMENT OF AGRICULTURE. 



Unit Value of the Calcium Oxide in Lime Manures. 



It has been very difficult to obtain definite information from 

 dealers with regard to the composition of the various lime manures 

 that are being offered for sale, and tlie writer has found by actual 

 analysis that tlie figures submitted in some cases are far from being 

 reliable. Therefore the attempt to arrive at an approximate unit 

 value for the calcium oxide has only been made in the case of the 

 agricultural limes. From the price lists and pamnhlets received 

 from most of the dealers in such materials it has been calculated that 

 the unit value o'f the calcium oxide (in the form of carbonate) in agri- 

 cultural limes, works out to approximately 6d., supposing the consign- 

 ment to be retailed per ton in bags, f.o.r. at the works, the price 

 including cost of bags as in fertilizers. 



Comparative Valuation of Lime Manures. 



By the aid of the calculated unit value given in the preceding 

 paragraph it is possible, as with a fertilizer, to ascertain whether a 

 certain agricultural lime is being- offered for sale at a fair vaine or 

 not, tor the estimated true market value could be calculated by 

 multiplying the unit value by the percentage of calcium oxide 

 piesent as u carbonate. But even without assuming the correctness 

 of this unit value as applied to lime manures we can compare two 

 agricultu]'al limes, for instance, and find out which is the better 

 value. 



To take an example, suppose a certain agricultural lime con- 

 taining 88 per cent, of carbonate of lime is quoted at £1. 2s. fid. 

 per ton, while another brand containing 95 per cent, of carbonate of 

 lime is being offered for £M . 8s. 6d., the terms of the sale being 

 identical in both cases. In the first brand every unit of carbonate of 

 lime is worth £1. 2s. 6d. -^ 88, or os. Id., while in the second the 

 price of carbonate of lime per unit works out to £1. 8s. fid. -^ 95, or 

 8s. fid., which is decidedh/ greater. 



Although the first agricultural lime works out to be the cheapei" 

 it may not really be so to a certain farmer when the item of carriage 

 is also taken into consideration, for in the case of such cheap bulky 

 materials as these this latter item is of great comparative importance. 

 In fact, before comparing prices, it is better to add in each case tlie 

 carriage and other incidental expenses of transport on to the dealer's 

 price f.o.r. at the works, for the total (T-ost of the consignment at the 

 farmer's owa door is the essential thing to know. 



Feeding Stuffs. 



Tlie number of artificial farm foods on the South African market 

 at the present time is so small that it is not out of the question to 

 attempt making out a list of unit values for each of the food con- 

 stituents, but a method Avill be exjjlained of comparing different 

 feeding stuffs with the view of ascertaining approximately their 

 relative value commercially. 



TJie Constituents of Foods. 



The regula;tions under the T:)reviously mentioned Act requires that 

 all dealers must give on their invoices a guarantee T^ith regard to the 

 composition of a farm food, stating tlie proportions present of the 



