Mr. Grant, and requested the privilege of
making a test on the wires of the company, which test if successful would
enable him to raise money. Mr. Grant promised to let him know when he
could make the test, but after nearly two years of waiting and
disappointment, Mr. Grant said that he had lost the drawings; and
although Meucci then made an instrument like the one shown in Fig. 9 for
the purpose of a test, Mr. Grant never tried it. Meucci claims that he
made no secret of his invention, and as instance cites the fact that in
1873 a diver by the name of William Carroll, having heard of it, came to
him and asked him if he could not construct a telephone so that
communication could be maintained between a diver and the ship above.
Meucci set about to construct a marine telephone, and he showed us the
sketch of the instrument in his memorandum book, which dates from that
time and contains a number of other inventions and experiments made by
him.

[Illustration: FIG. 9.--1864-65.]

[Illustration: FIG. 10.--1865.]

When Professor Bell exhibited his inventions at the Centennial, Meucci
heard of it, but his poverty, he claims, prevented him from making his
protestations of priority effective, and it was not until comparatively
recently that they have been brought out with any prominence.--_The
Electrical World._

* * * * *

AN ELECTRICAL CENTRIFUGAL MACHINE FOR LABORATORIES.

[Footnote: Paper read before Section B, British Association, Aberdeen
meeting.]

By ALEXANDER WATT, F.I.C., F.C.S.

The late Dr. Mohr[1] of Bonn, advocated the use of a centrifugal machine
as a means of rapidly drying crystals and crystalline precipitates; but
although they are admirably adapted for that purpose, centrifugal
machines are seldom seen in our chemical laboratories.

[Footnote 1: "Lehrb. d. Chem. Analyt. Titrirmethode," 3d ed., 1870, p.
684.]

The neglect of this valuable addition to our laboratory apparatus is
probably owing to the inconvenience involved in driving the machine at a
high speed by means of the ordinary hand driving gear, especially when
the rotation has to be maintained for a considerable length of time. It
occurred to me, therefore, that by attaching the drum or basket of the
machine (or the rotating table of Mohr's apparatus) directly to the
spindle of an electro-motor, the difficulty of driving might be got over,
and at the same time a combination of great efficiency would