The experiments undertaken with these substances demonstrated that those prepared by precipitating the nitro-starch with strong sulphuric acid were less stable in character or properties than those which were precipitated by water or weak sulphuric acid.  Dr Muehlhaeusen is of opinion that possibly in the former case a sulpho-group may be formed, which in small quantity may occasion this instability.

The following table shows the behaviour of these substances prepared in different ways and under various conditions:—­

_______________________________________________________

___________
|                     |                                            |
|                     |                  SAMPLES.                  |
|                     |____________________________________________|
|                     |        |        |        |        |        |
|                     |   A.   |   B.   |   C.   |   D.   |   E.   |
| Ignition-point      |175 deg.  C. |170 deg.  C. |152 deg.  C. |121 deg.  C. |155 deg.  C. |
| Stability           |Stable  |Stable  |Unstable|Unstable|Unstable|
| Per cent. of N.     | 11.02  | 10.54  | 12.87  | 12.59  | 13.52  |
| 96 per cent. alcohol|  Sol.  |  Sol.  | Insol. | Insol. | Insol. |
| Ether               | Insol. | Insol. | Insol. | Insol. | Insol. |
| Ether-alcohol       |  Sol.  |  Sol.  |  Sol.  |  Sol.  |  Sol.  |
| Acetic Ether        |  Sol.  |  Sol.  |  Sol.  |  Sol.  |  Sol.  |
|_____________________|________|________|________|________|_

_______|

These samples were prepared as follows:—­

A. From 1 part nitric acid and 2 parts sulphuric acid (containing 70 per
   cent.  H_{2}O). 
B. From 1 part nitric acid and water. 
C. From 1 part nitric and 3 parts H_{2}SO_{4} (con.). 
D. From 1 part nitric and 3.5 parts con.  H_{2}SO_{4}. 
E. From 1 part nitric and 3 parts con.  H_{2}SO_{4}.

Dr Muehlhaeusen is of opinion that these compounds may be turned to practical account in the production of good smokeless powder.  He recommends the following proportions and method.  Six grms. of nitro-jute and 2 grms. of nitro-starch are mixed together, and moistened with acetic ether.  These ingredients are then worked together into a uniform mass, and dried at a temperature ranging between the limits 50 deg. to 60 deg.  C. He has himself prepared such a smokeless powder, which proved to contain 11.54 per cent. of nitrogen, and was very stable.  Further details of Dr Muehlhaeusen’s work upon nitro-starch can be found in Dingler’s Polytechnisches Journal, paper “Die hoehren Salpetersaeureaether der Staerke,” 1892, Band 284, s. 137-143, and a Bibliography up to 1892 in Arms and Explosives, December 1892.