360 



Mr. C. Tomlinson on an Experiment 



the window of an inhabited room. The initial weight of the 

 pile at the beginning of the experiment at 5 p.m. on the 17th 

 October last was 422 grains ; on the 18th, at 11.30 a.m., the 

 weight was 416 grains. 





grams. 



grams. 



Oct. 19th, at 11, . 



. 406 



Nov. 1st, at 10.45, . 259 



20th, „ 10.30, 



. 391 



2nd, „ 10.30, . 253 



21st, „ 11, . 



.- 380 



3rd, „ 10, . . 243 



22nd, „ 12.30, 



. 366 



4th, „ 11.30, . 235 



23rd, „ 1.30, 



. 352 



5th, „ 10.30, . 226 



24th, „ 10.30, 



. 340 



6th, „ 10.30, . 219 



25th, „ 10.15, 



. 330 



7th, „ 11.30, . 210 



26th, no observation. 



8th, „ 10.30, . 202 



27th,. at 10.30, 



. 307 



9th, „ 10.45, . 195 



28th, „ 12, . 



. 296 



10th, no observation. 



29th, „ 11.30, 



. 286 



11th, at 11, . . 183 



30th, „ 10, . 



. 276 



12th, „ 10.30 . 178 



31st, „ 10.30. 



. 269 





During these observations the changes remarked by Mr. 

 Justice Grove as applicable to two slabs of stone applied 

 equally well to the two slabs of camphor. " If we suppose a 

 slab of stone [camphor] lying on another, both having flat 

 surfaces, the disintegration produced by changes of weather, 

 of temperature, &c, [evaporation] would act to the greatest 

 extent at the corners, and next to them at the edges, because 

 those parts expose respectively the greater surfaces compared 

 with the bulk of the stones [camphor]. This would tend to 



Fig. 3. 



round off all the angles, and gradually change the rhomb 

 more or less towards an oblate spheroid." 



The above description applies with great accuracy to the 

 changes that took place in the superposed blocks of camphor 

 (fig. 2), whether of the dimensions above indicated or on 

 larger blocks, namely 2^ inches. In such case the form be- 

 came reduced in the course of many months to flattened 

 oblate spheroids. In the case of the smaller masses which 

 were weighed from day to day, after the solid angles and 



