lO^ Kautical Instruction. 



which succeeds it, in the series. In the form adopted by Dr. 

 De Butts, the copper cases cannot be made, without a much 

 greater expense in the workmanship. Those which I have 

 used, are formed by machinery, so that they are very hand- 

 somely finished, with great rapidity, end all of one size and 

 shape. 



In consequence of this contrivance, a workman has under- 

 taken to furnish Deflagrators, at forty-five or fifty cents for 

 every Galvanic pair (seven inches by three) contained in 

 them. This is much lower than the Paris prices, for appa- 

 ratus far less powerful. 



I cannot discover the motive of Dr. De Butts, for having 

 the legs of his apparatus of glass — while, from the construc- 

 tion of his troughs within, he evidently sanctions my plan of 

 omitting insulation. Had I seen the glass legs, without being 

 aware of the internal construction of his battery, I should 

 have expected to find the inside partitioned by glass. 



Dr. De Butts speaks of the coils of Col. Offerhaus and Mr. 

 Pepys, as if that form of the Galvanic battery had originated 

 with them; whereas this was one of the forms, first contem- 

 plated by me — it was afterwards actually made by Dr Pat- 

 terson and Mr, Lukens, and in a much larger form by Mr. 

 Peale and Mr Wetheril!,* at least a year, I believe two 

 years, before it was resorted to, either by Pepys or Offer- 

 haus. 



II. Foreign. 



Foreign Literature and Science, selected and translated by Prof. Griscom. 



1. Sweden. — Mutual Instruction, — There are now in 

 Sweden sixty-seven schools of mutual instruction ; in which 

 the Lancasterian system is practised. Twenty-two of these 

 schools have been established since the commencement of 

 1823; there are thirteen in the capital. — Rev.Encyctopedique, 



* See memoir on a New Theory of Galvanism, Silliman's Journal, Vol. L 

 page 118— also Memoir on the Deflagrator, page 41. 



