Apparent Diminution of Weight in certain circumstances. 227 



4th. The fact may be explained by the more favorable action of 

 the muscles of the humerus during the transition from a forced inha- 

 lation to complete expiration in consequence of their connexion with 

 the muscles of respiration. It is not the loud that is lightened, but 

 the strength of the bearers that is more favorably applied, and the 

 apparent difference in weight during a successful experiment is no 

 greater than can be explained by this method. 



After being satisfied by actual trial, that the fact was a true fact. 

 the obvious inquiry appeared to be, whether the load was lightened 

 or the bearers strengthened. The former supposition seems to be 

 physically impossible, unless we can introduce some " new princi- 

 ple," or contrive some short way to dispose of the laws of gravity, 

 and as I did not think it advisable to attempt either, I was driven to 

 the necessity of accounting for the increased strength of the bearer. 

 And this increased strength, I conceive may be accounted for by re- 

 ferring to the relative situation of certain muscles at the time the ex- 

 ertion is made. The deltoideus, the supra spinatus and infra spina- 

 tus, are tense and ready to act, the ribs are elevated to the utmost 

 by the forced inhalation, the scapula is fixed by the action of the 

 muscles of the humerus antagonised by the serratus major anticus 

 and others. The lifting of the load and depression of the ribs, then 

 begin, the serratus muscle is directly affected by this depression, its 

 action is thereby rendered more energetic, and thus the muscles of 

 the humems attached to the scapula are seemingly strengthened. 

 It may be anatomically demonstrated, I think, that the action of the 

 above muscles in the given position would produce the supposed re- 

 sult, at least in degree. There may be a difference of opinion as to 

 the sufficiency of the cause to produce the effect. To this I could 

 only say, that owing to the peculiar insertion of these muscles of the 

 humerus, only a very trifling additional direct or indirect action on 

 their part would be necessary, as we have only to account for a tri- 

 fling difference in weight. During the most successful experiments 

 in which I performed the part of a bearer, the sensation of lightening 

 was no more than would have been experienced by the removal of 

 five or six pounds from my hand. If all four bearers experienced the 

 same it would make a difference of between twenty and thirty pounds 

 in the apparent weight of the load. This difference is trifling when 

 divided among four persons, but it is fully sufficient to account for 

 most if not all the prodigious facts generally narrated in connexion 

 with this experiment. When I hear of individuals weighing between 



