complete unily."* The steps in electrical attraction 

 were described as occurring on two different levels 

 of abstraction: first one has physical contact through 

 an effluvium or "spiritus" that connects the two 

 objects physically. Then, as a result of this contact, 

 the objects somehow sense '■" that a more intimate 

 harmony is possible, and move accordingly. Gilbert 

 called the motion that followed contact, attraction. 

 However, this motion did not connote what we would 

 call a force: ''' it did not correspond directly to a 

 push or pull, hut it followed from what one might 

 term the ap[)rehcnsion of the possibility of a more 

 complete participation in a formal irnity. The physical 

 unity due lo ihe "spiritus" was tiu' prelude to a 

 formal organic unity, .so that humor is "rerum omnium 

 unitore." Gilbert's jiosition can be best seen in 

 the following: ''■ 



Spii'llus igitur egredicns ex corpora, quod ab humore 

 aut succo aqueo concrcveral, corpus attrahenclum attingit, 

 atlactuin attrahenti unilur; corpus peculiar! eftiuviorum 

 radio conlinguum, ununi cffccit e.\ duobus: unita confluunt 

 in conjunctissimam convcnientiam, quae attractio vulgo 

 dicitur. Quae unitas iuxta Pythagorac opinionem rerum 

 oninium principium est, per cuius participalioncm una- 

 ([uacciue res una dicitur. Quoniam enim nullo actio a 

 materia potest nisi per contacluui. t-leclrica haer non 

 videnlur tangcre, sed ul necesse eral demillitur aliquid ab 

 uno ad aliud, quod proxime tangat, et eius incitationis 

 principium sit. Corpora omnia uniimtur & quasi ferrumin- 

 antur quodammodo humore . . . Electrica vero elfl via 

 peculiaria, quae humoris Aisi subtilissima sunt materia, 

 corpuscula allectant. Aer (commune effluvium tclluri 

 & partes disjunclis unit, & tellus mediante acre ad se 

 revocal corpora; alitcr quae in superioribus locis assent 

 corpora, terram non ita avide appelerent. 



Electrica effluvia ab acre multum differunt, & ut aer 

 telluris effluvium est, ita electrica suahabenl effluvia & 

 pro|)ria; peculiaribus cffluviis siius euique; est singularis 

 ad unitatem ductus, molus ad principiiun. fontem, & 

 corpus effluvia emittcns. 



A similar hypothesis will reap])ear in his explanation 

 of magnetic attraction. 



Following the tradition of the medieval schoolmen 

 Gilbert started his examination of the nature of the 



'" M: pp. 91, 92: "This unity is, according to Pythagoras, the 

 principle, through participation, in which a thing is said to be 

 one" (see footnote.", 30 and 122). 



120 "Sense" is probal)ly too strong a term, and yet the change 

 following contact is difTicuh to describe in Gilbert's phraseology 

 without some such subjeetive term. See Gilbert's argument on 

 the soul and organs of a loadstone, M: pp. 309-31. 'i. 



'2' M: pp. 112,113. 



'" Gilbert, De magnele. London, 1600, bk. 2, eh. 2, pp. 56-57. 



loadstone by pointing oiu the different kinds of 

 motion due to a magnet, llie li\e kinds (other than 

 up and down) are: '*^ 



(i) coilio (vulgo attractio. dicta) ad imilatem magneti- 

 cam incitatio. 



(2) directio in polos telluris. ct telluris in mundi destinatos 



terminos verticitas et consistentia. 



(3) variatio, a meridiaiio deflexio. t|uem ukjIiuh nos 

 depravaliun dicimus, 



(4) deeliiialio, infra horizonlem poli magiielici descensus. 



(5) motus circularis, seu revolutio. 



Of the five he initially listed, three are not basic 

 ones. V'ariation and declination he later ex[)lained 

 as due to irregularities of the suriace of the earlh, 

 while direction or vcrticity is the ordering motion that 

 ])rececles coition. '"^ This leaves only coition and 

 revolution as the basic motions. How these followed 

 from ""the congregant nature of the loadstone can be 

 seen when the effusion of forms has been considered."' 



Coition (he did not take up revoluti(}n at this 

 point) diHered from that due to other attractions. 

 There are two and onlv two kinds of bodies that 

 can attract: electric and magnetic.'"'' Cjilbert relined 

 his position further by arguing that one does not 

 even have magnetic attraction'"'' but instead the 

 mutual motion to unicjn that he called coition.'-'^ 

 In electric attraction, one has an action-passion 

 relation of cause and effect with an external agent 

 and a passive recipient : \\ hile in magnetic coition, 

 both bodies act and are acted upon, and both move 

 together. '^*' Instead of an agent and a patient in 

 coition,'"** one has "conactus." Ctoition, as the 

 Latin origin of the term denoted, is always a con- 

 certed action. ''" This can be seen from the motions 

 of two loadstones lloating on water.'" The mutual 

 motion in coition was one of the reasons for Gilbert's 

 rejection of the perpetual motion machine of Pcre- 

 grinus. '''^ 



Magnetic coition, unlike electric attraction, cannot 

 be screened.''^' Hence it cannot be corporeal for it 



'2' Ihid., ch. 1, pp. 45-46. 



i-< M: pp. lit), 314. 



'-•■' M: pp. 82, 105, 170, 172, 217. 



i!« M: p. 98. 



I-'' M: pp. 100, 1 12, 1 13, 143, 148. It need luiidlv be pointed 

 out that coitus is not an impersonal term. 



>2« M: p. 110. 



i» M: p. 1111. 



™ .VI: pp. 109, 115, 148, 149, 155, 166, 174. 



"1 M: pp. 110, 155. 



"2 M: pp. 166, 332. See also footnote 84. 



"' M: pp. 90, 106, 107, 108, 113, 132, 135, 136, 158. This 

 is, of course, contrary to modern experience. 



134 



BULLETIN 218: CONTRIBUTIONS FROM THE MUSKl'M ( )!• HISIORV .AND TECHNOLOGY 



