Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 16, 1883
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Supplementary Paper on Sorghum.
By Mr. Justice Gillies.

[Read before the Auckland Institute, 17th September, 1883.]

Since reading my paper on Sorghum at last meeting I have received from Dr. Hector the results of the Colonial Laboratory analysis of a one gallon jar of syrup sent him some four months after it was made. These results and the data they afford as to the commercial value of growing Sorghum for sugar production are of the utmost value. The following is the report:—

Syrup for proportion of cane and grape sugar— lbs. oz.
Weight of syrup separated from crystallized sugar 12 3
Weight of crystallized sugar therein 0 12 ½
Total 12 15 ½

At a temperature of 60°, specific gravity 1.406 water at 1.000, the syrup contained 71.60 per cent. of cane sugar. The syrup and sugar gave 7.15 per cent. of grape sugar.

lbs. oz.
71.6 per cent. upon 12lbs. 3oz. of syrup gives of sugar 8 11½
Sugar crystallized spontaneously 0 12½
Total cane sugar 9 8
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These results astound me, and prove Sorghum as a sugar producing crop to be valuable beyond my wildest imaginations. I proceed to the proof.

Three years' experiments have proved beyond a doubt that, on average soils, in an average season, with ordinarily decent cultivation, as for maize, the Early Amber Sorghum will, in the northern part of New Zealand, that is, from the Bay of Plenty (perhaps even from Napier) northwards, produce a crop of from 12 to 16 tons of cane per acre. Two years' experiments prove that from each ton of cane from 80 to 90 gallons of juice can be expressed by very inferior machinery. Two years' experiments prove that, if that juice is evaporated in an open evaporator down to 13–15 gallons (that is to say one sixth), a rich syrup results, which will remain unaltered by fermentation for many months. The analysis of the Colonial Laboratory proves that each gallon of this syrup, weighing about 13 lbs., contains 9 ½ lbs. of cane-sugar, besides 7.15 per cent of grape-sugar or glucose. That means that each ton of cane produces 9 ½ lbs. x 13 gallons (taking the lowest quantity) = 123 ½ lbs. cane-sugar; and that means that every acre produces (taking the lowest average of 12 tons cane) 1,482 lbs. cane-sugar, besides grape-sugar and other what may be called waste products, such as the leaves and seed—valuable for cattle- and fowl-feed. The value of this product of sugar, at £30 per ton, is nearly £20 per acre. This, it will be observed, is taking all the products at the lowest quantities actually produced. Probably the amount of sugar to syrup, 71.6, shown by analysis to be present, might not practically be secured; but, even allowing a large margin, the result is extraordinary. When I compare this with the latest American results taken from the St. Louis Republican of 30th November, 1882, kindly furnished me by Mr. Consul Griffin, it will be seen that the Early Amber Sorghum produces here a greater weight of cane and developes nearly double the quantity of sugar that it does in Illinois, where the Sugar Company at Champaign pays 10 per cent. The following is the extract referred to:—

“A company at Champaign, Illinois, which has recently made thorough experiments in the manufacture of Sorghum sugar, professes to have reached results in the highest degree satisfactory and convincing. The company's experiments were made on the cane grown on 200 acres, cultivated by itself, and that grown on 50 acres more by farmers in the neighbourhood. The latter was bought at $2 to $2 50 a ton. It has made 125,000 lbs. of fair sugar, worth 8 ¼ cents a pound, and 22,500 gallons of molasses worth 44 cents a gallon. This shows an average gross product of $80 per acre. What the nett product is we cannot tell

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without knowing the cost of the whole. A very accurate account of the outcome from 12 ½ acres of orange-cane was kept, which stands as follows:—

“9,600 lbs. sugar at 8 cents $768 00
“1,450 gallons molasses at 40 cents 580 00
“Total value of product $1,348 00
“Total expense, including cost of cane at $2 50 per ton, labour, superintendence, fuel, sugar and molasses barrels, interest on capital, and wear of machinery 704 54
“Nett profit $633 46
“Profit per acre 50 67

“This crop of twelve and one-half acres of early orange yielded 12 ½ tons of cane to the acre, which at $2 50 per ton, paid the grower $31 25 per acre for the crop. Twelve tons of early orange, and ten of early amber, are regarded as a fair crop. These yields are certainly encouraging, for they show that Sorghum cane will pay a farmer better than wheat; but they are not equal to the product of a well cultivated crop of sugar cane in Louisiana. The Champaign Company has paid out of the profits of its first year's business 10 per cent. on the cost of its buildings and machinery, 8 per cent. on its active capital, and laid aside $3,000 besides; and it is so greatly encouraged that it has determined to increase its capital stock from $25,000 to $50,000, expend from $8,000 to $10,000 for additional machinery, and cultivate 1,000 acres of land in cane next season.

“The Champaign experiment tends to prove, if it does not actually prove, that Sorghum-cane growing and sugar making may be made profitable industries in Illinois—not quite as profitable as sugar making from tropical cane in Louisiana, but still lucrative enough to become a permanent feature in western agriculture.”

After this I shall cease pitying a northern farmer who complains that he cannot make farming pay by raising wheat or potatoes or rearing beef and mutton, in all which the southern farmer can beat him, instead of taking to Sorghum and other crops more suitable to his soil and climate with which the south cannot compete.