138 Notices respecting New Books. 



4. That the greatest daily variation takes place either at, or 

 a little before and after, the sunimer solstice ; and the least at the 

 winter solstice. 



5. That the greatest daily variation happens now earlier in thje 

 day, than it did at the beginning and middle of the last century. 



6. And lastU', that the daily variation is less at the equator 

 than in our latitudes. 



Mr. B. then proceeds to explain that all these peculiarities are 

 the necessary consequences of supposing the sun to possess ^ 

 certain degree of magnetic influence, such as that which belongs 

 to every mass of plain unmagnetized iron ; and of admitting the 

 existence of the plane of no attraction, and the other magnetic 

 laws indicated in the preceding part of this article. He shows, 

 for instance, that at one time in the year the sun will, both at 

 its rising and setting, be above the pjane of no attraction j that 

 at another it will both rise and set below tiie plane ; while at 

 )Otl»ers it will rise above and set below, &c. ; and that this con- 

 sideration fully explains those modifications in the daily variatjjon 

 as denoted above. He shows, moreover, that the least daily va- 

 riation ought to happen at the winter solstice, the rectangle (siii 

 2 A.. COS /.) being then the least ; that there ought to be a second 

 minimum at the summer solstice, aithoiigh the rectangle (sin 

 2 A. cos /.) is then much greater than in the former instance; 

 ftnd that a little before and after this solstice the daily variation 

 ought to be at its maximum. He proves also, that if 14' be 

 reckoned the greatest daily variation in our latitude, it ought not 

 to exceed 3' at the equator j and lastly, that it ought to be 

 jiothing or very inconsiderable during the night. 



We will not presume to give a very decided opinion as to the 

 accuracy of the above view of this interesting phenomenon ; 

 but we venture to say, that it is by far the most complete illus- 

 tration of it that has ever yet been offered, and that we have 

 little doubt it will be generally adopted. 



Description of an Apparatus, by which 25,000 cubic Feet of Gas 

 are obtained from each Chaldron of Coal, without producing 

 either Tar or annwnical Liquor. By Samuel Clegg, Civil 

 Engineer, Mavvbey- place, South Lambeth, Surry. 8vo. pp. 16, 

 with a large Plate of the Apparatus. 2s. 



In his introductorv remarks Mr, Clegg, who has had more ex- 

 perience, and introduced more improvements in the manufactur- 

 ing of coal gas, in the large way, than perhaps any person who 

 has applied his time and talents to this bramii, after alluding to 

 the n«mero'i6 i'nprove;n€»ts previoutly introdoced bjj himself, 



and 



