8 
rorULAR SCIENCE REVIEW. 
Mr. Stringfellow bimself sa}\s, “Wit.li respect to the super- 
posed planes, I consider they are the most practical arrange- 
ments hitherto proposed, for machines on a large scale, but I 
had always my doubts if they would be effective in a small 
model on account of their nearness to each other.” 
Fig. 2 (Plate XXXVI.) is from a photograph of Stringfellow’s 
aerial machine which ran suspended from a wire in the nave 
of the Crystal Palace, June 1868. 
It contained in its three planes, a sustaining surface of twenty- 
eight square feet, besides the tail. Its weight, with engine, 
boiler, fuel, and water, was under twelve pounds. 
It possessed in its steam-engine one third of the power of a 
horse, and its weight was only that of a goose. 
It will be seen, therefore, that the sustaining surface was 
more than two feet to the pound, always supposing that the 
system of superposing the planes, was efficiently represented in 
so small a model, which may reasonably be doubted. This pro- 
portion of weight to surface is more than double that, which 
is generally allowed to be necessary. The necessity, however, 
for providing even for as little as one pound for every square 
foot, would not exist if a certain speed could be maintained. 
It was always ^Ir. Stringfellow’s intention to set this model 
off free in the air, when the requirements of the exhibition were 
satisfied, but it was found that the engine, which had endured 
much work, required repairs. It had been observed by several 
reporters for the press that the model showed a decided tendency 
to an upward course during its hundred yards run at the Crystal 
Palace, and anxious to see it afterwards liberated, the writer 
assisted to hold the canvas which should check its fall. 
The space at hand for the horizontal wire was small, and did 
not allow of sufficient speed being attained, before its liberation 
by a simple mechanical action. When freed from its support it 
descended an incline with apparent lightness, until caught in 
the canvas, but the general impression conveyed was this — that 
had there been sufficient fall, it would have recovered itself, and 
proceeded onwards. 
Subsequently, Mr. Stringfellow lengthened the propellers, 
and added nine feet to the central plane, which, with other alte- 
rations, decidedly deteriorated its aerial capabilities. 
He is now engaged in experimenting with a view of ultimately 
constructing a large machine that would be sufficient to carry a 
j>erson tr> guide; and conduct it. On this scale he would avoid 
many difficulties which are inseparable from small models. 
As Mr. Stringfellow gained the prize of 100^. for “the 
lightest steam-engine in proportion to its power,” and as the 
engine which propelled the model at the Crystal Palace differed 
from that but in dimensions, it will only be necessary to append 
