Inthismakeshiftlaboratoryweworkedpracticallyunaidedduringtwoyears,occupyingourselvesasmuchwithchemicalresearchaswiththestudyoftheradiationoftheincreasinglyactiveproductswewereobtaining.Thenitbecamenecessaryforustodivideourwork.PierreCuriecontinuedtheinvestigationsonthepropertiesofradium,whileIwentaheadwiththechemicalexperimentswhichhadastheirobjectivethepreparationofpureradiumsalts.Ihadtoworkwithasmuchastwentykilogrammesofmaterialatatime,sothatthehangarwasfilledwithgreatvesselsfullofprecipitatesandofliquids.Itwasexhaustingworktomovethecontainersabout,totransfertheliquids,andtostirforhoursatatime,withanironbar,theboilingmaterialinthecast-ironbasin.Iextractedfromthemineraltheradium-bearingbariumandthis,inthestateofchloride,Isubmittedtoafractionalcrystallization.Theradiumaccumulatedintheleastsolubleparts,andIbelievedthatthisprocessmustleadtotheseparationofthechlorideofradium.Theverydelicateoperationsofthelastcrystallizationswereexceedinglydifficulttocarryoutinthatlaboratory,whereitwasimpossibletofindprotectionfromtheironandcoaldust.Attheendofayear,resultsindicatedclearlythatitwouldbeeasiertoseparateradiumthanpolonium;thatiswhyweconcentratedoureffortsinthisdirection.Weexaminedtheradiumsaltsweobtainedwiththeaimofdiscoveringtheirpowersandweloanedsamplesofthesaltstoseveralscientists,inparticulartoHenriBecquerel.
Duringtheyearsand,PierreCuriepublishedwithmeamemoironthediscoveryoftheinducedradioactivityproducedbyradium.Wepublishedanotherpaperontheeffectsoftherays:theluminouseffects,thechemicaleffects,etc.;andstillanotherontheelectricchargecarriedbycertainoftherays.And,finally,wemadeageneralreportonthenewradioactivesubstancesandtheirradiations.
PierreCuriewiththequartzpiezo-electroscopeheinvented,bywhichraysofradiumaremeasuredfortheCongressofPhysicswhichmetinParisin.Myhusbandpublished,besides,astudyoftheactionofamagneticfieldonradiumrays.
Themainresultofourinvestigationsandofthoseofotherscientistsduringtheseyears,wastomakeknownthenatureoftheraysemittedbyradium,andtoprovethattheybelongedtothreedifferentcategories.Radiumemitsastreamofactivecorpusclesmovingwithgreatspeed.CertainofthemcarryapositivechargeandformtheAlpharays;others,muchsmaller,carryanegativechargeandformBetarays.Themovementsofthesetwogroupsareinfluencedbyamagnet.Athirdgroupisconstitutedbytheraysthatareinsensibletotheactionofamagnet,andthat,weknowto-day,arearadiationsimilartolightandtoX-rays.
Wehadanespecialjoyinobservingthatourproductscontainingconcentratedradiumwereallspontaneouslyluminous.Myhusbandwhohadhopedtoseethemshowbeautifulcolorationshadtoagreethatthisotherunhoped-forcharacteristicgavehimevenagreatersatisfactionthanthathehadaspiredto.