ORDER OP THE AMERICANKNIGHTS.A VALLANDIQHAM RIVOLCTIONART PLOT.A few days since the St Louis papers gave an account of the arrest of twenty-six persons, detected^ after long watching, Id the holding of meetings at two weii known seceah public houses of that city, for the purpose of plotting treason. The developments connected with this arrest seem likely to prove important. The Cincinnati Commercial of Thursday has a letter from St. Louis, which says:“ The lift time I wrote you I hid the distinguished honor of a clese proximity to the eel* of lh* British Lloa, h*Tl»f, la foot, written from Windsor, Oootda West, t told you, at the time, of a t!»U to Valland-Ighats, by a United Stott* •fflclel who waa w*U koowo te bo a •ympatblsor with the baniehed on* j but now that th* military, aathoritloa of this olty bar* laid haadi apoa tha Individual In question and sent himto spend th* iumraer In Gratiot street prison, you matt kaow hi* name and a* much of tho history ef tht orrest as It 1* possible to obtain.. Hen. Oharl** L. Hoot, th* Belgian Comal of tbi* oily, wet arrested nearly three weeks ago, a simple paragraph In tha dally papers hers, being the only *»outward and risible sign of hta “ arbitrary with* drawal fromlhe private and public walks of life. A short time bsfors his arrest. Uncle Abraham had tha temerity te revoke Hr. Hunt's consulete.and Cop* porhsad circles are all astir at the turn affaire hart takan. In order to fatty appreciate the Importance of this arrset, It Is necessary to state that at fho time of Hunt’s vlell to Vattandlgham, at Wind sbr, there was a meeting there of the new Order known as tha American Knlghte, aa organlsattoa made out of the •battered materlels of the Knlghte of the Golden Circle, and ef which Vellesdlgham fe the Grand Commander. The rebel Geo. Pries Is the great Mogul of tha American Knlghte, and a regular chain of communication u formed between hie army and the North, throagh the medium of V deserters,” amnesty proslaaatleolste, and women devoted to the cease of the South. It !• believed that Hunt is and has been the Saanelal agent of tho rebels la Missouri, and that all the echemsa of Jsff. Davis A Co., concerning this corner of theSoathern vineyard, were oondacted bySlice hla arreet U has come to light that the order of American Knights I* of national extent, and, numerically, a pewsrful organisation. In thU Stattit numbtrt 80 OiK); HUnoit 160,000. ntarly 100.000 q/tthom art armed ; Kentucky 70.000, hal/oftchom are a mtd. TA* Stott o/Ntw Jertty% Jftw York and Stnntylvania are ttrongly organised, and tht work of organisation it going on rapidly in Michigan, Witconein, Iowa and oUttr WttUrn StQUt Sold and daring at it may item, it it tht dttign cf ths Amtrioan JCnigMt to convoy Vatlandigham to tomt Jiorthtrn city on tht Uhof July, and op only rt*Ut tht Oovtmmtnt, by nominating him /or tht Srttidtnoy. This, It 1* expected, will cause a revolution In the North, and help to turn th« scale in favor of the South. Whether Consul Hunt is deeply Involved iu thle aew scheme of the Valiant)Ighamers or not, ha ha* beta sufficiently Identified with them to cause his at rest by ths military, who hold him and positively refuse to releass him on ball.”TIi# Bssults tff Volunteering andCi •;d89,'tltlt;kciIibCiciili