Rotary Pump from Serviere.

285

Chap. 5.]

turn close to those of the case, so that water cannot enter between them.The axle of one of the wheels is continued through one side of the case,(which is removed in the figure to show the interior,) and the openingmade tight by a stuffing box or collar of leather. A crank is applied to the

end to turn it, and as one wheel revolves,it necessarily turns the other; the direc-tdon of their motions being indicated bythe arrows. The water that enters thelower part of the case is swept up theends by each cog in rotation, and as itcannot return between the wheels in con-sequence of the cogs being there alwaysin contact, it must necessarily rise in theascending or f'orcing pipe. The machineis therefore both a sucking and forcingone. Of rotary pumps this is not onlyone of the oldest, but one of the best.Fire engines made on the same plan werepatented about twenty-five years ago inEngland, and more recently pumps ofthe same kind, in this country. We haveseen one with two elliptical wheels,which were so geared that the longeraxis of one wheel might coincide (in oneposition) with the short one of the other. Sometimes a groove is madealong the face of each cog, and a Strip of leather or other packing se-cured in it.

The pump figured above is believed to have been known long beforeServiere’s time, a model of it, as of other interesting machines, havingbeen placed in his museum without regard to its origin. Ramelli is saidto have described some similar ones in the middle of the 16th Century,but we have not been able to procure a copy of his book. The suctionpipe in the preceding figure has been added. In the original the waterentered directly through the bottom of the case : the model was probablyso made that part of the wheels might be visible, and the construction andOperation of the machine more easily comprehended.

Serviere was a French gentleman, born at Lyons in 1593. Indepen-dent in his circumstances, and inclined to mechanical researches, he wasled to establish a cabinet of models of rare and curious machines—ofthese some were invented by himself and displayed uncommon ingenuity.It does not appear that any account of the whole was ever published ; apart only being included in the small volume edited by his grandson, thetitle of which we have given at the f’oot of page 63. That work is dividedinto three parts: the first relates to figures formed in the lathe, as spheres,cubes, ellipses, &c.; some, being hollow and containing others withinthem, like Chinese balls, are extraordinary specimens of workmanship.There are also vases, urns, &c. not only round and elliptical, but angular,so that not only were the oval and eccentric chucks known to Serviere,but the lathe for turning irregulär surfaces appears to have been used byhim. The second part contains an account of clocks all made by himself,the mechanism of which is exceedingly ingenious. Some are moved bysprings, others by weights, water, sand, &c. They are fully equal to anything of the kind at the present day : indeed that beautiful device bywhich a small brass ball is made to traverse backwards and forwards acrossan inclined plane, which still retains a place among mantel clocks, is one

No. 131. Rotary Pump from Serviere.