319 



been found at various heights from the seed to the third joint : they 

 would seem to enter the pupa state about the beginning of June. 



This fly was not observed by Miss Morris to inhabit any other 

 plant than wheat. 



To prevent the ravages of this destroyer of the grain, it will be proper 

 to obtain fresh seed from localities in which the fly has not made its 

 appearance. By this means the crop of the following year will be un- 

 injured; but in order to avoid the introduction of straggling insects of 

 the kind from adjacent fields, it is requisite that a whole neighbour- 

 hood should persevere in this precaution for two or more years in 

 succession. This result was obtained, in part, in the course of trials 

 made by Mr. Kirk, of Bucks County, Pa., with some seed-wheat from 

 the Mediterranean, in and since the year 1837. His first crop was 

 free from the fly, but it was gradually introduced from adjacent 

 fields; and in the present year the mischief has been considerable. 

 As Miss Morris states that the fly has never made its appearance in 

 Susquehanna and Bradford Counties, seed-wheat, free from the fly, 

 might be obtained from these, and probably from other, localities. 



The Committee recommend that the conclusion of Miss Morris 

 " may be subjected to the only efficient test — repeated observations 

 and effective trials of the precaution she advises." 



The Committee, consisting of Prof. Rogers, Dr. Bache, and 

 Mr. Booth, on a communication, entitled, "On the Perchlorate 

 of Ethule or Perchloric Ether, by Clark Hare and Martin H. 

 Boye," reported in favour of publication, which was ordered 

 accordingly. 



In the above paper, the mode of obtaining the perchloric ether, by 

 subjecting a mixture of sulphovinate of baryta and perchlorate of ba- 

 ryta to distillation, is first described. The authors next detail the 

 precautions to be attended to in preparing and experimenting upon 

 this highly explosive compound. They afterwards describe the ap- 

 pearance and properties of the substance which ranks in that class 

 of organic salts, denominated ethers. It is a colourless, transparent 

 liquid, heavier than water, and soluble in alcohol, from which it may 

 be precipitated again, by the addition of water. An alcoholic solu- 

 tion of the hydrate of potassa has the power of decomposing it, form- 

 ing perchlorate of potassa and alcohol. The most characteristic pro- 

 perty of the compound is its tendency to explode from the slightest 

 causes 



