to the Method of Least Squares. 213 



1869 DoRXA. 'Sulla media arithmetica vel calcolo di compensa- 

 zione.' Atti. Acead. Torino, Vol. IV, pp. 757-763. 



On Encke's demonstration of the arithmetical mean, and on 

 ScHiAPARELLi's article of 186S. 



1869 FaX de Bruno. '•Tralt'e elementaire du calcul des erreurs, 

 avec des tables stereotypees, ouvrage utile d ceux qui cultivent les sci- 

 ences d'' observation.'' Paris, 8vo, pp. vii, 72, xly. 



The tables are the best part of this ouvrage, but in that giving 

 the values of sin" there is at least one dangerous error. This was one 

 of the first books on the Method of Least Squares which I read, 

 and I take this opportixnity to warn young students against it. The 

 text is full of typographical and other errors and the subject is pre- 

 sented neither clearly or fully. The list of literature at the end does 

 not contain the names of Legendre, Ivory, Encke, Bessel, Ellis, 

 or Herschel, gives only one w^ork by Hansen, and does not men- 

 tion Gauss's Theoria motus The book deserves a speedy 



oblivion. 



1869 Galton. '■Hereditary Genius ; an Inquiry into its Laws 



and Consequences.'' London, 8vo. — Amer. edition, 1870. 



The exponential law of error is used in dividing mankind into 

 grades of intellect. Quetelet's numbers (1846) are employed for 

 this purpose and are given in the appendix. 



1869 Hansen. ' Entwickehmg eines neuen veranderten Yerfahrens 

 zur Ausgleichung eines Dreiecksnetzes mit besonderer Betrachtung 

 des Falles in welchem gewisse Winkel voraus bestimmte Werthe be- 

 kommen sollen.' Abhandl. Sachs. GeselL, Vol. XIV, pp. 185-287. 



1869 Helmert. ' Beitrage zur Theorie der Ausgleichung trigonom- 

 etrischer Netze.' Zeitschr. Math. u. Phys., Vol. XIV, pp. 174-208. 

 See Jahrb. Fortschr. Math., Vol. II, p. 835. 



1869 Jordan. ' LTeber die Bestimmung der Genauigkeit mehrfach 

 wiederholter Beobachtungen einer Unbekannten.' Astron. JVachr., 

 Vol. LXXIV, col. 209-226. 



Contains a method for finding probable errors from the |w-(/i— 1) 

 differences between n observations taken two by two. See below 

 AndrI. 



1869 Andea. ' Schreiben [om Bestemmelsen af den sandsynn- 



lige Fell ved Hjaelp af lagttagelsernes Diffentser].' Astron. JVachr., 

 Vol. LXXIV, col. 283-284. 



Objects to Jordan's method on the ground that the differences are 

 not independent. See 1872 for contiiuiation of this discussion. 



