1820.] Philosophical Transactions for 1819, Part I. 45 



One hundred parts of starch decomposed in contact of air 

 yielded 



Sugar 49-7 



Gum 9-7 



Amyhn 5-2 



Starchy hgnin 9*2 



Lignin mixed with charcoal 0"3 



Starch not decomposed 3-8 



77-9 



These experiments being repeated with potatoe starch, and 

 continued only for 42 hours, yielded the following products : 



In vacuo. 



Starch 35-4 304 



Gum 17-5 17-2 



Amylin 18-7 17-0 



Starchy lignin 7*0 4-4 



Lignin with carbon Trace 0-2 



Starch uudecomposed 9-4 9*3 



88-0 78-5 



Loss during analysis 6*0 



94-0 



When the starch was decomposed in vacuo, it rather gained 

 than lost weight. The apparent loss was owing to the starch 

 not having been dried before the experiment at a temperature so 

 high as 212°. No water was formed, and the carbonic acid 

 evolved was mixed with a portion of hydrogen gas, pure, or at 

 least containing only a very small portion of carbon. 



IV. On Corpora Lutea. By Sir Everard Home, Bart. 

 According to the author of this paper, the corpora lutea make 



their appearance at the age of puberty. They are composed of 

 convolutions similar to the brain ; their use is to form the ova. 

 These, when formed, are expelled by the corpora lutea, whether 

 impregnation has taken place or not. Sometimes the ovum 

 remains in the corpus luteum without being expelled. In such 

 cases (supposing impregnation) a fcetus will be formed in the 

 ovarium. 



V. Remarks on the ProhahiUties of Error in physical Observa- 

 tions, and on the Density of the Earth, considered especially loith 

 Regard to the Reduction of Experiments on the Pendulum. By 

 Thomas Young, M.D. For. Sec. R.S. 



Tliis paper consists of four parts. The first part, which is by 

 far the longest and most elaborate, is employed in the applica- 

 tion of the science of probabilities to estimate the advantage of 

 jjiultiplied observations. After some judicious observations on 



