JOHN FLAMSTEAD. 159 



with a Sliort Treatise, explaining the Ordinary Operations of Arith- 

 metic, &c., presented to His Most Excellent Majesty Charles 11. 

 by S. Morlandjn 1692." This work, which is exceedingly rare, 

 but of which there is a copy in the Bodleian, which bears date 

 1673, 8vo, is illustrated with twelve plates, in which the 

 different parts of the machine are exhibited ; and whence it 

 appears that the four fundamental rules in arithmetic are very 

 readily worked, and to use the author's OAvn words, " without 

 charging the memory, disturbing the mind, or exposing the 

 operations to any uncertainty." That these machines were at 

 the time brought into practice there seems no reason to doubt, 

 as by an advertisement prefixed to the work it appears that 

 ihey were manufactured for sale by Humphrey Adamson, who 

 lived with Jonas Moore, Esq., in the Tower of London. 



The speaking-trumpet is said to have been invented by Sir 

 Samuel Morland in 1670. His trumpet was of the same form 

 as that now in use — that is to say, it was a truncated cone, 

 v/ith an outward curve or hp at the opening. 



" The theory of the action of this instrument," says one 

 writer, "has never been thoroughly explained; but it is 

 supposed that the sides of the tube throw the sound back and 

 back in various reflections, until ultimately the waves quit the 

 instrument in parallel lines. It does not seem to depend on 

 the vibration of the instrument." 



JOHN FLAMSTEAD. 



John Flamstead, the great astronomer, who wns a contem- 

 porary of Sir Isaac Newton, was led to the study ot astronomy 

 by perusing Sacrobosco's work, " De Sphiera." He prosecuted 

 his studies with so much assiduity as to be appointed first 

 Astronomer-Royal. His grea" work is entitled " Historia 



