n　be　obtained　in　a　laboratory。　Any　one　who　pleases　is　at　liberty　to　convince　himself　of　the　reality　of　the　facts；　provided　that　he　applies　to　genuine　mediums　and　keeps　aloof　from　the　inferior　〃seers〃　and　especially　the　shams　and　imposters　who　swarm　in　this　region　more　than　in　any　other。　Even　with　the　best　of　them；　he　will　have　to　be　careful　of　the　involuntary；　unconscious　and　almost　inevitable　interference　of　telepathy；　which　is　also　very　interesting；　though　it　is　a　phenomenon　of　a　different　class；　much　less　surprising　and　debatable　than　pure　psychometry。　He　must　also　learn　the　art　of　interrogating　the　medium　and　refrain　from　asking　incoherent　and　random　questions　about　casual　or　future　events。　He　will　not　forget　that　〃clairvoyance　is　strictly　limited　to　the　perception　of　human　personality；〃　according　to　the　role　so　well　formulated　by　Dr。　Osty。　Experiments　have　been　made　in　which　a　psychometer；　on　touching　the　tooth　of　a　prehistoric　animal；　saw　the　landscapes　and　the　cataclysms　of　the　earth's　earliest　ages　displayed　before　his　eyes；　in　which　another　medium；　on　handling　a　jewel；　conjured　up；　it　would　seem　with　marvellous　exactness；　the　games　and　processions　of　ancient　Greece；　as　though　the　objects　permanently　retained　the　recollection　or　rediscovered　the　〃astral　negatives〃　of　all　the　events　which　they　once　witnessed。　But　it　will　be　understood　that；　in　such　cases；　any　effective　control　is；　so　to　speak；　impossible　and　that　the　part　played　by　telepathy　cannot　be　decided。　It　is　important；　therefore；　to　keep　strictly　to　that　which　can　be　verified。
  Even　when　thus　limiting　his　scope；　the　experimenter　will　meet　with　many　surprises。　For　instance；　though　the　revelations　of　two　psychometers　to　whom　the　same　letter　is　handed　in　succession　most　often　agree　remarkably　in　their　main　outlines；　it　can　also　happen　that　one　of　them　perceives　only　what　concerns　the　writer　of　the　letter；　whereas　the　other　will　be　interested　only　in　the　person　to　whom　the　letter　was　addressed　or　to　a　third　person　who　was　in　the　room　where　the　letter　was　written。　It　is　well　to　be　forearmed　against　these　first　mistakes；　which；　for　that　matter；　in　the　frequent　cases　where　strict　control　is　possible；　but　confirm　the　existence　and　the　independence　of　the　astounding　faculty。
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  As　for　the　theories　that　attempt　to　explain　it；　I　am　quite　willing　to　grant　that　they　are　still　somewhat　confused。　The　important　thing　for　the　moment　is　the　accumulation　of　claims　and　experiments　that　go　feeling　their　way　farther　and　farther　along　all　the　paths　of　the　unknown。　Meanwhile；　that　one　unexpected　door　which　sheds　at　the　back　of　our　old　convictions　more　than　one　unexpected　door；　which　sheds　upon　the　life　and　habits　of　our　secret　being　sufficient　light　to　puzzle　us　for　many　a　long　day。　This　brings　us　back　once　more　to　the　omniscience　and　perhaps　the　omnipotence　of　our　hidden　guest；　to　the　brink　of　the　mysterious　reservoir　of　every　manner　of　knowledge　which　we　shall　meet　with　again　when　we　come　to　speak　of　the　future；　of　the　talking　horses；　of　the　divining…rod；　of　materializations　and　miracles；　in　short；　in　every　circumstance　where　we　pass　beyond　the　horizon　of　our　little　daily　life。　As　we　thus　advance；　with　slow　and　cautious　footsteps；　in　them　as　yet　deserted　and　very　nebulous　regions　of　metapsychics；　we　are　compelled　to　recognize　that　there　must　exist　somewhere；　in　this　world　or　in　others；　a　spot　in　which　everything　is　known；　in　which　everything　is　possible；　to　which　everything　goes；　from　which　everything　comes；　which　belongs　to　all；　to　which　all　have　access；　but　of　which　the　long…forgotten　roads　must　be　learnt　again　by　our　stumbling　feet。　We　shall　often　meet　those　difficult　roads　in　the　course　of　our　present　quest　and　we　shall　have　more　than　one　occasion　to　refer　again　to　those　depths　into　which　all　the　supernatural　facts　of　our　existence　flow；　unless　indeed　they　take　their　source　there。　For　the　moment；　that　which　most　above　all　engage　our　attention　in　these　psychometric　phenomena　is　their　purely　and　exclusively　human　character。　They　occur　between　the　living　and　the　living；　on　this　solid　earth　of　ours；　in　the　world　that　lies　before　our　eyes；　and　the　spirits；　the　dead；　the　gods　and　the　interplanetary　intelligences　know　them　not。　Hardly　anywhere　else；　except　in　the　equally　perplexing　manifestations　of　the　divining…rod　and　in　certain　materializations；　shall　we　find　with　the　same　clearness　this　same　specific　character；　if　we　may　call　it　so。　This　is　a　valuable　lesson。　It　tells　us　that　our　every…day　life　provides　phenomena　as　disturbing　and　of　exactly　the　same　kind　and　nature　as　those　which；　in　other　circumstances；　we　attribute　to　other　forces　than　ours。　It　teaches　us　also　that　we　must　first　direct　and　exhaust　our　enquiries　here　below；　among　ourselves；　before　passing　to　the　other　side；　for　our　first　care　should　be　to　simplify　the　interpretations　and　explanations　and　not　to　seek　elsewhere；　in　opposition；　what　probably　lies　hidden　within　us　in　reality。　Afterwards；　if　the　unknown　overwhelm　us　utterly；　if　the　darkness　engulf　us　beyond　all　hope；　there　will　still　be　time　to　go；　none　can　tell　where；　to　question　the　deities　or　the　dead。
  CHAPTER　III。　THE　KNOWLEDGE　OF　THE　FUTURE
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  Premonition　or　precognition　leads　us　to　still　more　mysterious　regions；　where　stands；　half　merging　from　an　intolerable　darkness；　the　gravest　problem　that　can　thrill　mankind；　the　knowledge　of　the　future。　The　latest；　the　best　and　the　most　complete　study　devoted　to　it　is；　I　believe；　that　recently　published　by　M。　Ernest　Bozzano；　under　the　title　Des　Phenomenes　Premonitoires。　Availing　himself　of　excellent　earlier　work；　notably　that　of　Mrs。　Sidgwick　and　Myers＇1＇　and　adding　the　result　of　his　own　researches；　the　author　collects　some　thousand　cases　of　precognition；　of　which　he　discusses　one　hundred　and　sixty；　leaving　the　great　majority　of　the　others　on　one　side。　Not　because　they　are　negligible；　but　because　he　does　not　wish　to　exceed　too　flagrantly　the　normal　limits　of　a　monograph。
  ＇1＇　Proceedings；　Vols。　　V。　and　XI。
  He　begins　by　carefully　eliminating　all　the　episodes　which；　though　apparently　premonitory；　may　be　explained　by　self…suggestion　（as　in　the　case；　for　instance；　where　some　one　smitten　with　a　disease　still　latent　seems　to　foresee　this　disease　and　the　death　which　will　be　its　conclusion）；　by　telepathy　（when　a　sensitive　is　aware　beforehand　of　the　arrival　of　a　person　or　a　letter）；　or　lastly　by　clairvoyance　（when　a　man　dreams　of　a　spot　where　he　will　find　something　which　he　has　mislaid；　or　an　uncommon　plant；　or　an　insect　sought　for　in　vain；　or　of　the　unknown　place　which　he　will　visit　at　some　later　date）。
  In　all　these　cases；　we　have　not；　properly　speaking；　to　do　with　a　pure　future；　but　rather　with　a　present　that　is　not　yet　known。　Thus　reduced　and　stripped　of　all　foreign　influences　and　intrusions　the　number　of　instances　in　which　there　is　a　really　clear　and　incontestable　perception　of　a　fragment　of　the　future　remains　large　enough；　contrary　to　what　is　generally　believed；　to　make　it　impossible　for　us　to　speak　of　extraordinary　accidents　or　wonderful　coincidences。　There　must　be　a　limit　to　everything；　even　to　distrust；　even　to　the　most　extensive　incredulity；　otherwise　all　historical　research　and　a　good　deal　of　scientific　research　would　become　decidedly　impracticable。　And　this　remark　applies　as　much　to　the　nature　of　the　incidents　related　as　to　the　actual　authenticity　of　the　narratives。　We　can　contest　or　suspect　any　story　whatever；　any　written　proof；　any　evidence；　but　thenceforward　we　must　abandon　all　certainty　or　knowledge　that　is　not　acquired　by　means　of　mathematical　operations　or　laboratory　experiments；　that　is　to　say；　three…fourths　of　the　human　phenomena　which　interest　us　most。　Observe　that　the　records　collected　by　the　investigators　of　the　S。　P。　R。；　like　those　discussed　by　M。　Bozzano；　are　all　told　at　first　hand　and　that　those　stories　of　which　the　narrators　were　not　the　protagonists　or　the　direct　witnesses　have　been　ruthlessly　rejected。　Furthermore；　some　of　these　narratives　are　necessarily　of　the　nature　of　medical　observations；　as　for　the　others；　if　we　attentively　examine　the　character　of　those　who　have　related　them　and　the　circumstances　which　corroborate　them；　we　shall　agree　that　it　is　more　just　and　more　reasonable　to　believe　in　them　than　to　look　upon　every　man　who　has　an　extraordinary　experience　as　being　a　priori　a　liar；　the　victim　of　an　hallucination；　or　a　wag。
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  There　could　be　no　question　of　giving　here　even　a　brief　analysis　of　the　most　striking　cases。　It　would　require　a　hundred　pages　and　would　alter　the　whole　nature　of　this　essay；　which；　to　keep　within　its　proper　dimensions；　most　take　it　for　granted　that　most　of　the　materials　which　it　examines　are　familiar。　I　therefore　refer　the　reader　who　may　wish　to　form　an　opinion　for　himself　to　the　easily…accessible　sources　which　I　have　mentioned　above。　It　will　suffice；　to　give　an　accurate　idea　of　the　gravity　of　the　problem　to　any　one　who　has　not　time　or　opportunity　to　consult　the　original　documents　if　I　sum　up　in　a　few　words　some　of　these　pioneer　adventures；　selected　among　those　which　seem　least　open　to　dispute；　for　it　goes　without　saying　that　all　have　not　the　same　value；　otherwise　the　question　would　be　settled。　There　are　some　which；　while　exceedingly　striking　at　first　sight　a