The cooperative industrial program of the Allies and the United States had to be geared into the shipping problem. To do this the determination of what materials should be shipped from the United States had to be decided first on the basis of what economies could be effected in shipping space. If raw materials for aircraft occupied less cargo space than the finished product, the maximum utilization of available tonnage demanded the shipment to France of these raw materials to be made into the finished product there. If, on the other hand, finished nitrocellulose powder for artillery shell propellants, or finished picric acid for artillery shell explosives, occupied less cargo space than the raw component materials used in their production, the shipping shortage demanded manufacture of these explosives and propellants in the United States. Not a single ship could be freighted with an extra pound or cubic foot of cargo which by any effort could be saved.
The French Mission in the United States early recognized this fact and urged the manufacture in the United States of picric acid to be used as explosive in 75-millimeter and 155-millimeter shell, pointing out that the finished product occupied but one-nineteenth as much cargo space as the raw materials.
Gen. Pershing recognized the point, and in August, 1917, cabled as follows:
A joint French-American commission has examined the question of the production in France of powders and explosives and reports as follows: France must import by December 4 the greater part of the raw materials used in the manufacture of powders and explosives. The weight of raw materials required is 10 to 20 times the weight of the finished product. The shipping situation is such that by December the output of France will be limited by the amount of raw material produced in France or easily obtainable. * * * The present outlook is that in December the French output will not be more than half of the present output. To avoid calamity the United States must not only furnish powder and explosives for all of its own forces but must supply about half of the French requirements. It is therefore recommended: (A) that the United States Government furnish all powders and explosives needed for present contracts with French Government; (B) that the United States Government prepare to furnish by December 300 tons per month of explosives and 200 tons per month of powder for French consumption; (C) that study be immediately commenced for the purpose of adapting American powders to French cannon of different types, this study to be made both in the United States and in France by competent experts; (D) that the French Government put at the disposition of the American Government competent experts both in the manufacture and use of these powders in the guns. * * *
Subsequent computations made on this side of the ocean indicated that in the case of picric acid and other explosives this ratio between raw materials and finished product in bulk was too great, yet in principle these computations did not affect the desirability of shipping the finished product rather than the raw materials.
Again, Gen. Pershing cabled to the Chief of Staff in the United States urging the purchase of completed artillery, artillery ammunition, and airplanes abroad, in order that "saving of tonnage" might be effected, and pointing out the saving of cargo space resulting from the shipment to France of raw materials instead of finished products, saying:
Following is comparison in tonnage of the principal manufactured articles of ordnance obtained in Europe and the replacements in raw materials contracted for the same. All tonnage ratios shown are in favor of raw materials:
| Field Artillery guns | 1 to 7½ |
| 155 millimeter howitzers and ammunition | 1 to 1¼ |
| 8 millimeter ammunition | 1 to 3-3/16 |
| Trench mortars | 1 to 12⅓ |
| Grenades | 1 to 4 |
| In airplane production: | |
| Packed airplanes, in weight | 1 to 2 |
| Packed airplanes, in cubic capacity | 1 to 2½ |
| Packed airplanes in area covered by boxes on board ship | 1 to 9 |
In the above comparison in the ammunition item, finished explosives are regarded as raw materials.